For Season 4 of Sea of Thieves, developer Rare added six new Siren Shrines, each packed with puzzles and unique loot to discover. The Shrines are very well realized and have a lot of detail, and exploring all of them is well worth your time. The Shrine of the Coral Tomb tasks players with discovering the remains and journals left behind by less-fortunate adventurers who had failed to plunder the Shrine’s treasures in the past.
Before you can begin your treasure-hunting and puzzle-solving, you have to get inside the Shrine of the Coral Tomb. You can locate the Shrine’s location by heading for the Shores of Plenty, on the H5 quadrant of your sea map. When you get to its approximate location, you will notice bright lights emanating from the water — stop your ship in that exact spot and dive straight down.
After a couple of seconds of swimming, you should be able to see the top of the Shrine of the Coral Tomb, rising over a mound of colorful rocks and coral growths. Use your compass to orient yourself and aim for the Northwestern facing of the mound. There you will see the entrance to the shrine.
To open the water gate, hit the round flashing ornament just above it. You will be allowed into the Shrine of the Coral Tomb, or at least a sort of antechamber at the top of it. From here the only way to go is down a beautiful water-slide, which will take you to the main portion of the Shrine.