Overview of Mile Marker 4

Mile Marker 4

The Big Island
Hawaiian Islands


Mile Marker 4 is small beach with easy entry. Several lava tubes may be found a short swim to the left.

Directions: Mile Marker 4 is, as the name implies, found right at the 4 mile marker of Ali'i Drive just south of Kailua.


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03/15/2018 Anonymous (Avg: 3.02 Review) - An easily accessible spot with interesting topography and a decently healthy reef. Dove here in March on a day when there was very little surf. Entry and exit are easy IF it's calm, but would be rough if there was any surf to speak of. We chatted with a local diver there who told us he had once gone in with no surf at all, then come back to find 5 ft surf that forced him to swim up to adjacent Magic Sands Beach to exit. It's the ocean... respect it and don't try this one if it's not calm. Once in the water we headed left, exploring around the lava fingers along the way. Some people here have been calling these lava tubes but they are more like little canyons. This is fairly shallow, around 30 feet or less. We did follow the reef further out to about 50 feet at one point. The coral is pretty bleached in spots but there are healthy areas too. We saw many small reef fish (the usual suspects such as tangs, parrots, and wrasse) as well as a dragon wrasse and a puffer. The visibility was not great for Kona- probably about 30 feet. Overall a fun dive although not spectacular.

02/25/2018 William (Avg: 3.10 Review) - Good topography dive, with many fish species in residence. Previous descriptions of entry are accurate - dive MM4 only when swell is calm. Coral has experienced heavy bleaching here, yet pockets of health remain. Sighted one turtle, which gave us a nice flyby.

07/29/2017 David R. (Avg: 3.54 Review) - This was a very enjoyable site. My wife and I did two dives there in July of 2017. I have found this website to be an invaluable resource. We decided that the easiest entry would be to assemble our equipment and tanks by the water and float the BCDs out about 6 meters from shore to waste high water. There we put on our fins and BCDs and started to head out. Having our feet on the sand and lava rock without fins and a tank on our back made the entry super smooth. This is a nice snorkeling spot as well because there is probably about 100 meters of water no deeper than 3 meters. You need to kick out 100 to 150 meters to get to depth. There are some nice lava tubes to swim through between 6 and 10 meters of depth. We saw turtles and plenty of fish life. we didn't really get deeper than 12 meters and kept it nice and easy. This was an easy and relaxing site that is very close to Kailua Kona town center.

05/31/2016 Mike Byrne (Avg: 4.21 Review) - 5/29/2016 Dove with my wife Katie and friend Jordan Forth who also is my personal trainer. Water conditions were great with exceptional visibility. We swam through the cave then onto the reef and sand flats. We came across a large conch which made for great pictures. Lots of tropical fish and plenty to see. Great place to dive !

05/22/2016 Mike Byrne (Avg: 4.18 Review) - 5/21/2016 Dove with my wife Katie. Water conditions was great with 70+ feet of visibility. Lot of tropical fish and turtles. Found a couple of conchs at cave entrance which made for some great photos. Swam South to 50 feet of water and spotted an eagle ray feeding in the sand flats. Nice sunny day had a great dive.

03/20/2016 Mike Byrne (Avg: 3.00 Review) - 3/20/16 Dove with my wife Katie and friend Capt. Alan Borowski. Had some swell entering wasn't bad but exiting was difficult. Lots of tropical fish. Large conch eating a star fish at cave entrance. Saw a couple of turtles on the way in. Water was a little murky do to swell but still had a great time.

08/17/2015 Shirley (Avg: 2.84 Review) - Difficult entry and exit, lots of urchins. Full suit is recommended, not for warmth, but for getting tore up on the rocks. Many people come out with cuts, including 2 or 3 in our group. Cool cave and decent fish life, but would probably skip it if any surge or surf at all.

06/26/2015 Kerri Whitlow (Avg: 2.86 Review) - This was a fun site to dive once we got past the waves breaking on shore. There are lots of lava rocks loose and rolling in the surf. Standing sideways as the waves broke on us made it much easier. With our fins on, Ben, Lisa, and I made our way out to the sandy spot where Lisa completed skills for her certification. She did great and then we headed south for a tour of the area. We missed the swim through on that dive. Lots of health corals and quite a few fish. We finished the dive in the cove that we entered the water and helped each other on the way out. We had planned a second dive but the beach at the north end of the parking area had been closed due to a sighting of a large Tiger Shark. That was only a few hundred yards away so we chose to skip the second dive. Ben and I came back a few days later in the vacation to find the lava tube swim through. We chose the same entry with success and once we were in the water swam along the south edge and at 20+ feet we found the opening. We had fun swimming through and got some video using the go pro. The chimneys go up to within 10 feet of the surface or so. A very fun dive and I will do that one again next time I am on island.

05/05/2015 Kerri Whitlow (Avg: 2.86 Review) - This was a fun site to dive once we got past the waves breaking on shore. There are lots of lava rocks loose and rolling in the surf. Standing sideways as the waves broke on us made it much easier. With our fins on, Ben, Lisa, and I made our way out to the sandy spot where Lisa completed skills for her certification. She did great and then we headed south for a tour of the area. We missed the swim through on that dive. Lots of healthy corals and quite a few fish. We finished the dive in the cove that we entered the water and helped each other on the way out. We had planned a second dive but the beach at the north end of the parking area had been closed due to a sighting of a large Tiger Shark. That was only a few hundred yards away so we chose to skip the second dive. Ben and I came back a few days later in the vacation to find the lava tube swim through. We chose the same entry with success and once we were in the water swam along the south edge and at 20+ feet we found the opening. We had fun swimming through and got some video using the go pro. The chimneys go up to within 10 feet of the surface or so. A very fun dive and I will do that one again next time I am on island.

02/26/2015 Tim H. (Avg: 3.77 Review) - Dove this last week with my 12 yr old daughter and 14 yr old son. As mentioned in earlier reviews, the loose, rocky 'beach' makes hauling and gearing up some work, but the narrow sandy channel is OK for entry as long as the surf isn't too bad. We waited a couple of days to do this site due to conditions and even though it had improved, you still had to be careful. The diving itself was great - both the lava tube and arch were impressive, and the coral was much healthier than Two Step. Great spot for beginners/intermediates like us - would've gone back if we had another day!

03/18/2014 Ann Geiger (Avg: 3.32 Review) - This is a local favorite, because it is an easy dive with a large variety of fish. We saw many different kinds of butterflyfish, as well as tangs, surgeonfish, hawkfish, triggerfish, damselfish. Several moray eels and a crab. Minor coral bleaching but reef looks healthy overall. Saw two other dive buddy pairs. To the left (south) in about 25 feet of water there is a small lava tube that you can easily swim through and then either turn around or pop up in 10ish feet of water. We swam out to the edge of the reef then swam along the sand edge for a ways, turning around at a pinnacle (hit our max depth of 50' there). Swam back in at around 25' (checked out the lava tube). The dive site itself is at mile marker 4 but the entry to the parking area is between 3 1/2 and 4, just past a small sandy beach. Park at the far end of the lot (we were able to get one of the last spots around 10:15 am). Gear up at your car, then walk through the small opening in the wall and down the path to the lava rock beach. Toward the middle of the beach there is a small sandy channel that makes entry and exit easier. Walk out past the surf zone, don your fins, and away you go!

02/17/2014 Jayne (Avg: 3.32 Review) - I've snorkeled here multiple times and dove here recently. I've never had a great experience. The reef and animal life are great but getting to them is horrid. The rock entry makes hauling gear tough, the surf is unpredictable. I'm a new diver. I was in a group of 5 divers, only TWO came out not bleeding and cut up or not needing stitches. Personally, I lost a booty, a fin, a snorkel and cracked my mask on the rocks. Despite the wicked surf getting in and out...if you're experienced this is an awesome dive! Lots of beautiful things to see, lots of fish. There is an arch if you go out past the sand patch. Good luck, wear booties and gloves, watch for sea urchins and waves.

06/29/2013 Mike from Honolulu (Avg: 2.38 Review) - Easy access by car, short walk over loose rocks for entry with a slight hill. Parking is limited there is no sandy area. There is an arch but is it shallow and we missed it-- one of the people we were with that was snorkeling with saw it-- there is a decent lava tube.

09/26/2012 Kelly 1 (Avg: 3.83 Review) - This was our 3rd dive for the day. We weren't sure we would find the lava tubes on our first outing, but we found them fairly easily. We snorkeled out about 1/3 of the way out of the bay and then dropped down - it was only about 10' for us - and then kept going out with a slight angle to the left. We went up and down several of the fingers of the lava tubes and finally found the ones with the arch swim through and the tunnel that ended with a chimney opening. We looked up and could see that the surge was pretty heavy at the time, so we opted not to go up and instead went back out the way we came in. We most likely would have had better vis had we come earlier in the day, but we wanted to do 2-step/Place of Refuge in the morning since we heard that place gets packed - glad we did because we had the 1st dive to ourselves. But about 4 Mile - it's a fun, short dive with not much sea life for us, though I know a shark can sometimes hide out in that tunnel. I read the info here and was planning to park on the street as the photos indicated but found the parking lot just to the north to be easier and closer to the 'sandy' entry (note, the sandy entry area is small but definitely doable). The rocks near the entry were large enough to set our BCDs/tanks and sit down to get everything fastened after getting our mask defogged. My buddy and I are both Intermediate Divers with 20-30 dives and enjoyed this dive as a variation from our other 2 shore dives at Place of Refuge.

09/15/2012 Tracy RIdeout (Avg: 3.16 Review) - Very nice dive, easy access from the little rocky beach. short swim out into the cove and drop down to 20'. We followed the reef system out to the sandy bottom at about 35' and looked around the reef system for about 35 minutes, then swam south to the lava tubes and arch swim through. That was pretty cool. We saw a big hawksbill turtle sleeping on the bottom a spotted moray and lots of fish. I was looking for the reef trigger, but didn't find one. All in all, a very nice shore dive and lots of fish. Swim throughs were fun and the lava tube was pretty cool. Went through the cave and up through the little sky light. Easy swim back. There's a shower at the beach to the north, but we didn't use it.

11/26/2011 Samantha (Avg: 3.53 Review) - Pretty great dive. Very easy in. The out on the second dive was a bit tougher due to surge, but nothing insurmountable or dangerous. Saw a nice sleeping turtle in the back of a pretty cool and easy to navigate cave. Will likely go back here before we leave the island. One beginner diver and one advanced diver and we both had fun.

07/30/2011 Cranbrook Dave (Avg: 3.99 Review) - First time diving this site. Early start for easy entry, great visibility (70+ ft) and lots to see. Great diversity of fish, porcupine puffers, razor, triggers to name a few. A few snorkelers. Dive/snorkel boats stopped near by to see dolphins, we could hear but not see the dolphins. Lots of features to engage all levels of divers. Capped off by an inquisitive green turtle. Best dive this trip, We will return.

04/16/2011 Paul D. (Avg: 3.05 Review) - This was our second dive of the day. I must say what a bummer that we had such big expectations for this dive. We set ourselves for failure by forgetting that mother nature is still in charge. The surge was heavy. Our buddy, upon entry got pummeled and not realizing lost half of his weights. The sandy bottom had things too kicked up, so vis was poor. We did manage to see an eagle ray, before buddy called the dive because he was not able to stay down before he realized that his weights were missing. There is always next time. Aloha.

09/26/2010 Nate (Avg: 3.37 Review) - The reviews below are true. The shark cave off to the left is great. The opening is a coral canyon that steepens into an overhang that frames the entrance in 30' depth. The first tunnel is about 20' long (10' wide) and empties into a sunlit chamber. The second tunnel is shorter but MUCH narrower (5' wide) and empties into a smaller sunlit chamber but NO SHARK today. :-( Remainder of dive was GREAT. The amount of invertebrate life is amazing. Crown of Thorns Starfish, Helmut Shell Conches, Tuxedo Urchins galore and too many fish types to name.

09/21/2010 Jerry & LaRea Birt (Avg: 3.32 Review) - We dove this site early in the morning, which was a good thing, as the parking lot filled up. The entry was a little difficult on account on the swells. But this is a very good dive. The lava tube is well worth the effort. We saw a turtle on our way out, and the Horned Helmet Shells out in the sand were an interesting find.

08/06/2010 Mike Groves (Avg: 3.68 Review) - Just a quick update as it has not been evaluated in the past few years. Really nothing has changed. Saw 2 turtles, one on our way out and one coming in. Also saw a very active eel just outside cove, which surprised me as it was 10am. The lava tube was a highlight and reason enough to make this dive. I will do this one again when we return.

11/08/2008 Bugaball (Avg: 3.76 Review) - Great place, easy access. There is a nice cave off to the left of the cove, where we were told sometimes there is a reef shark in the cave in the morning- didn't see it. The cave is a safe and easy entry/exit. Easy navigation, nice reef, easy water entry and exit. Some snorkelers when we took of, and two other divers. Good fun.

12/21/2007 Brian Xavier (Avg: 4.32 Review) - Great dive. Easy entry with great vis. Park in the lot next to the cove and go through the rocky surf straight out into the cove. Dove to 40 feet and very nice dive. No people around except a few snorkelers.

12/18/2007 Sarah Kneisel (Avg: 3.16 Review) - We dove this sight a couple times during really high surf. Entry was no problem as we could wait for a period of low surf but I got really banged up upon exit (bruises - no blood). The rough surf contributed to poor visibility, but I could tell it would have been a great site during low surf. There are great caverns and little caves. We saw a few morays and lots of fish. Definitely worth trying when the conditions are right.

08/15/2007 Anonymous (Avg: 3.50 Review) - Entry a little tricky, so just go slow. Nice cave off to left with sleeping turtles and other creatures in little crevices. After looking at the cave, you can follow the reef to the left or swim straight out over the sand to a second reef.

08/12/2007 Steve Porter (Avg: 4.72 Review) - This was the last dive I got to do with my father when he was visiting in Feb 2006 (he passed away on 06-04-07 and will be missed). It was a super duper easy entry, navigation was a snap, and heard whales…and they were close. Vis was about 80 ft due to that 40 days of rain we'll never forget. Saw a manta ray, and LOTS of crabs!!!! Not too sure if they are protected in this area. If you don't do this one while on the Big Island, you're robbing yourself!

07/01/2007 Maria (Avg: 4.80 Review) - Dove here on 6.27.2007. What can I say… THE BEST shore dive I ever had, and very few boat dives I have had can beat it! Great everything: access, entry, visibility, coral, underwater relief. There was a very curious dwarf moray :), brittle stars, octocoral and nudibranches in the lava tubes to the left! Turtles! Also saw a lagoon triggerfish (humuhumu-like but with bright blue stripes) for the first time. Had to face an offshore current on the way back but not too bad. There is an extremely convenient place to gear up right where the guard rail and trail head meet (someone installed a kind of shelf there :)

06/09/2006 Pam O (Avg: 3.73 Review) - Great dive if staying in Kailua-Kona. Good parking on either side. There are shower facilities for after the dive. Short walk down to the entry, rocky but easy to navigate to the water. Easy in and short snorkel. Nice reefs, caves, and lava tubes. Abundant fish life. Locals in the area say there are three caves with sharks and guarding them, but we did not find the sharks.

06/01/2006 Scooter Schneider (Avg: 3.85 Review) - This was my first dive at Mile Marker 4. There was a good surge and wave action and, although I had no problem, the wife was getting beat up a little. Once in, it's a wonderful dive with lots of swim throughs and caverns after you go around the point to the left. We saw several Lizardfish and turtles. Viz was a bit poor until we went around the point to deeper water and then it was good. There were surfers to the right and I thought it might be fun to grab an ankle. Next time ;)

12/15/2005 Chad Gordon (Avg: 3.98 Review) - Nice dive with easy shore entry. Had fun with 2 eagle rays and saw numerous turtles. Good dive to do as a second one in a day. Head out to the left and there are plenty of lava tubes to swim through.

08/17/2005 Joanne Evans (Avg: 3.94 Review) - This was our last dive on the Big Island before we had to come home. What a way to end our vacation! This was a great dive with the lava tubes and the turtles and fish. But I did not like the entry as it was very rocky and I was nervous about all the black Sea Urchins. There is parking on the right hand side (free) right next to the beach.

08/21/2004 Bill Benton (Avg: 3.13 Review) - Nice easy dive, short walk from parking. Good area for multiple dives. Best in the morning.

03/19/2004 Chuck Knauf (Avg: 3.38 Review) - I always dive this site while visiting Kona. Nothing to add to the other reviews. HOWEVER...Between Nov. '03 and Mar. '04, the handy wall to gear up on has grown. Land owner next to the site raised the gear-up wall to about 5 or 6 feet. We have to gear up the hard way now. *sigh*

03/19/2004 Rick Inman (Avg: 3.11 Review) - There is a nice lava tube swim through here, some interesting structure and a few pukas, and the location makes this a quick easy dive if you're staying in town, but otherwise I would drive to better sites. I wanted to make a night dive here, but never got to. I lost my knife here rolling in on the rocks, so if you found it, enjoy!

11/17/2003 Mark Wilson (Avg: 3.65 Review) - Great site. It was our first dive in Hawaii. The Lava Tube was interesting with plenty of life. The surge however was a bit tiring. Overall, This was a very easy place for beginners.

09/25/2003 Eric Crawford (Avg: 3.25 Review) - This is great site, especially if staying in Kona. The parking, entry, and surface swim is a breeze. The dive is definitely a shallower one, with max depth of about 35 feet. The lava tube/s we found were great with a couple turtles feasting in the back of them. There is great coral growth with lots of fish and easy navigation. I would really recommend doing this dive once during the day then again at night. I think the coral formations and the easy access would make for a great night dive.

01/22/2003 Barry Fackler (Avg: 4.31 Review) - A great dive site in the summer but a hit-or-miss proposition in the winter when NW swells drive the surf right into this little cove. In Summer 2002, a parking lot was added just north of this site by the county. You can gear up in this lot and walk down a narrow path to the entry. This is nice because parking is limited along the wall on Ali'i Drive. An added bonus is the shower & toilets @ the north end of the lot (for adjacent Magic Sands Beach Park). Once in the water, the best variety of terrain is to the left (south). There is a series of lava tubes, canyons, and caverns in this direction. Outstanding variety of tropical reef fish here. Saw 6 Green Sea Turtles on a single dive in this area. Lots of Whitemouth, Undulated, & Yellowmargin Morays. You can stay shallow & explore the reef tops or go 40 to 60' and check out the canyons. In a couple of caverns you can see uncommon Wavy Cave Sponges on the wall. This is a good place to find mollusks like Tiger Cowries, Leopard Cones, Triton's Trumpets & Day Octopi. Heading straight out can also be a good dive. In the shallows you can spot Lagoon Triggerfish and Dragon Wrasse. In around 20', my wife & I once saw 2 White-tip Reef Sharks tucked under a ledge. Further out, on the sand flats I've seen big Horned Helmet shells, Kona Crabs, and Blackside Razorfish that dive headfirst into the sand when you approach. Bluefin Trevally patrol out here also. The sand flats are also home to a couple colonies of Antler Coral each standing around 3 feet above the otherwise featureless terrain. When exiting the water, it's best to wait for any sets to pass. The bottom is really rocky and uneven and just a relatively small wave can knock you over. Likewise, the path that leads up to Ali'i Drive is strewn with loose coral rock that can easily make you lose your footing.

08/06/2002 Kim (Avg: 3.76 Review) - This is a great spot - always stay in Kona, so its a convenient place to dive. Did a night dive here this trip - very cool! Saw a very large crab, many smaller crab, shrimp everywhere, slipper lobster - the differences between day and night are amazing.

08/04/2002 Bill Stohler (Avg: 2.78 Review) - When the surf's down, this is a pretty easy and nice dive. It's just 5 minutes South of Kona town, and there are a few parking spots along the guard rail. The beach is comprised of well-rounded rocks, so watch your footing. On my second time there, we were out swimming out over the sand flats in about 60 feet, and saw a manta ray resting on the bottom. Good reef, and topography. Good beginner to intermediate diving, or if you just want something close to town.

07/18/2002 Mike Dinmore (Avg: 3.56 Review) - I enjoy this site. Good site for the novice and intermediate diver. Nothing advanced about the area, so don't pack your twin 80's. Beautiful cave out and to the left of the bay. Keep your eyes open for blackside razor fish while in the sand patches.

04/17/2002 Jon Knight (Avg: 3.78 Review) - This is a great stand-by site. Be careful of the entry and exit. Take your time. Very nice cave to the left and some surprising activity straight out from shore on small coral beds at 40'. I've found some interesting things out there. Haven't dove here at night yet, but I've heard it's good. With a chance of coming face to face with the caves evening resident.

01/23/2002 Rob (Avg: 4.16 Review) - This is a fun spot, been there about 20 times, never gets tiring. The wall along the road is great for gearing up. Sometimes you see other divers, but normally it just snorkelers. It's a quick trip to get tanks filled too. The tubes are fun, and sometimes there are turtles in the tubes. Try going around the other way (north) it's shallow, and gets a bit surgy, but I've seen more turtles on this side.

09/10/2001 Jim Goodenough (Avg: 3.59 Review) - I love this dive. The wall along the road is the perfect height to rest your tank when gearing up. The entry is tough since there are waves and slippery rocks. Love the lava tubes and turtles.

07/16/2001 Nydia White (Avg: 3.54 Review) - Fairly easy site. Watch the wave action. The entry/exit is challenging if the surf is up. The site is pretty shallow for quite a while and if there is a lot of surge you need to be careful about getting "high-sided". Very convenient area with the wall along the road to gear up. Easy access from the road to the shoreline. This site has a lot to offer and you will not see everything in one dive. I loved the channels and exploring down each one. This dive can easily be done while staying relatively shallow. Good for any experience level. Watch your air...it's easy to get pretty far away from the entry without realizing it. Save enough air to get all the way back.

06/03/2001 Roger Johnson (Avg: 3.56 Review) - Having done at least 500 dives at this site in the past 20 years, I have to say it's getting better with age. Manta's, Eagle Rays, Octopus, lots of Green Sea Turtles. Night dives with White Tips guarding the opening of the lava tube, what a thrill! Take a u/w scooter and see a beautiful reef at 80 ft. It's loaded with fish.


Site Photos

(click photo for a larger version)

 Map     Sat
GPS: TB1001


Parking at Mile Marker 4 

Parking is ample, next to the lava wall. The trail head is where the wall and the guard rail meet.


 Map     Sat
GPS: TB1002


Entry at Mile Marker 4 

The dive entry is just to the right, and the sights will be found to the left.




Aerial at Mile Marker 4 
(click photo for details)

Pick a calm day to do this dive, as the water can become cloudy from the adjacent beach.

Last Verification: September, 2000  


Diver Averages for  Mile Marker 4  (1=worst, 5=best)

Average Site Condition

Ease of Shore Entry:  3.13
Bottom Conditions:  3.84
Reef Conditions:  3.96
Animal Life:  3.80
Plant Life:  2.98
Facilities:  2.78
Solitude 3.29
Roads:  4.36
*Site Average:  3.55

Average Enjoyment Level

Snorkel:  3.53
Beginner Scuba:  4.07
Intermediate Scuba:  4.18
Advanced Scuba:  3.71
Night diving Scuba:  3.42

Number of reviews for this site: 45


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