You can’t eat or drink underwater which makes healing or renewing your Fria Curry or Lazarus Chowder a problem - Megalodons can swim straight up and straight down unlike some other aquatic mounts and when surfaced, you can dismount and stand on them to eat or use healing tonics. With enough HP you can set them to passive and let them tank damage from a Megalodon while using your rifle to dart the wild megalodon for a faster KO. Always best to have a few sharks with you while exploring the oceans.
1. Take an icthy
2. Go into the ocean and find a meg
3. Tranq it out in shallow water (you don’t have to in shallow water but if you tranq it in the deep, make sure it’s near the surface so you can breathe)
4. Boom you have your killing machine
1. Reinforce your raft with stone foundations, they won't be able to break them.
2. Make them attack your raft and shoot at them with tranq arrows (Bow and crossbow can both be used but a crossbow will be quicker) when they swim away because they are almost unconscious make sure you hit all the arrows you shoot so they won't escape.
3. Tame them with the food of your choice (high level Megalodons will need some narcotics or bio toxin, you won't need it immediately but be prepared).
4. Have fun with your Megalodon!
Getting one megladon makes getting more a lot easier. For what ever reason it aggros wild ones quite far. Just swim underwater and spy class the one you want. Lead it to the coast and begin tanqing. As for underwater usage. My 225 6k health and 364 melee was able to take an alpha megladon solo. I did manage to kill a lvl 70 alpha but needes help from rexes. Fairly good underwater would recommend 2 or more for higher level alphas though.