Sword of the Sea has 50 secret shells to be collected throughout the game. Secret shells are required to be collected for the following trophies & achievements:
- Lost Grotto Shell Collector
– Find all the secret shells in the Lost Grotto. - Forbidden Valley Shell Collector – Find all the secret shells in the Forbidden Valley Shell Collector.
- Shadow Tundra Shell Collector – Find all the secret shells in the Shadow Tundra.
- Frozen Drifts Shell Collector – Find all the secret shells in the Frozen Drifts.
- Sacred River Shell Collector – Find all the secret shells in the Sacred River.
- Boiling Cavern Shell Collector – Find all the secret shells in the Boiling Cavern.
- Water Whisperer
– Find all secret shells.
Secret shells are collectibles spread throughout the game, typically in well hidden or hard to reach places. Collecting all 50 unlocks the ability to use water rails in any level, not just in Sacred River. They are glowing white shells that are collected by going near them.
In the pause menu you can see how many total secret shells you have collected, but there is no tracker by chapter/area. Nothing is missable, everything can be collected through Chapter Select and carries over into New Game+.
Secret Shell Locations
Veiled Sea
Secret Shell #1 – In the area with the half pipe below the vendor, on the left of the half pipe is a hole in the wall leading to the shell.
Secret Shell #2 – After restoring the water around the pillar on the left in the large open area, look toward the waterfall under where the stele can be found and enter the cave on the right side of it to find the shell.
Secret Shell #3 – In the large open area keep to the left wall where you can find a group of lanterns on a slope. Turn them on to reveal an entrance, then go inside and activate the second set of lanterns to lower the sand inside the cave. Follow the path into the cave on the left to reach a water point. To the right of the stele is a small cave entrance. Bounce up the jellyfish inside and follow the path to the left where a new water point found. After activating the water a wall ride appears on the left. Use it to reach the platform at the end to find the shell.
Secret Shell #4 – After activating the main water point that activates the left chain, go to the top of the building above the vendor and look at the statue on the left where you can spot a shell on top. To reach it you need to ride one of the Orca that are swimming around when it goes near the statue, then jump on top to reach the shell.
Secret Shell #5 – Go back outside of the building facing where the chain is leading and look off the ledge to the left to spot two pillars lower off the side of the area. Gain speed and then jump toward the closer of the two pillars to find a Secret Shell. You can get back to the main area by jumping to the second pillar and using 
on the hole to be warped back.
Secret Shell #6 – On the opposite side of the building you can travel across the narrow waterfall and drop down to a ledge with a cave. In the cave you can find this shell.
Secret Shell #7 – In the area where the second chain is located after dropping the sand by interacting with the button in the center of the area, follow the left wall up the cliff to a path with a wall ride. On the other side you can find the Secret Shell.
Secret Shell #8 – After activating the main water point to activate the right side chain, go behind the building and up the waterfall with the kelp. From the top of the waterfall follow the path to the right along the cliff until you reach the area with the stone walkways leading off the cliffs. Go out onto the one faster right (relative to the central area) and look down and left to spot a flag on the cliff. Beside the flag is a cave containing the Secret Shell.
Secret Shell #9 – Keep following the path along the same cliff to where there are more walkways leading down. Drop to the lowest level to find the frog on the lowest level on a stack of rocks, then look down where there is a statue below. Jump down to it where the shell is on the small cliff beside it.
Secret Shell #10 – When going back to the main area either grind the chains or use the kelp to reach the cliffs on the right. On the cliffs just before the large central area you can find the shell in a small sandy area.
Lost Grotto
Secret Shell #11 – In the area with the two turtle heads follow the path onto the rooftops above where the stele is located and jump into the window behind the sand waterfall to find the shell.
Secret Shell #12 – Go through the door to progress and in the room where you see the figure jump from the ledge on the far side of the area, drop off the ledge into the hole in the ground. At the bottom you can find the secret shell in a large pipe.
Secret Shell #13 – After activating the next water point go up onto the rooftops where you can find a stele in an open building. Behind the building where the stele is, there is an open walkway with the shell.
Secret Shell #14 – Activating the main water point in the area that activates the chain to open the exit, go around the back of the giant shark statue where you can ride up the back to find the shell at the top.
Secret Shell #15 – In the area with the tall buildings where you activated the switches, you can drop down to the lowest level where one building has a shell in an open room.
Secret Shell #16 – Ride the first chain to the top of the buildings in the center of the area. On this rooftop you can find the shell in a small tunnel on the rooftop.
Secret Shell #17 – From the same rooftop as above, go to the end of the water path to the single building at the end. Off the side of this building you can find the shell on a ledge.
Secret Shell #18 – Ride the second chain back to the first area, then from the rooftop near the chain climb up the cliff on the left to find the shell at the end of the path.
Secret Shell #19 – Follow the rooftop from the chain pillars back toward the start of the area. The shell is in an open section of the building right near the wall.
Secret Shell #20 – In the first area on the rooftops near the large wallride you can use kelp to reach a ledge going above the wallride. Follow the path into a cave to find the shell.
Secret Shell #21 – Follow the chain toward the end of the area, but instead of going into the building jump around the ledges on the right side of the building. At the end you can find a small cave with this shell.
Forbidden Valley
Secret Shell #22 – In the section of the area with the three water crystals go up the platforms to the second level after the first crystal. Instead of activating the lanterns to reach the next crystal, follow the path around to the right and jump up the ledges. At the top is a set of lanterns between the green crystals. Activate them to make a jellyfish appear, which allows you to jump to the far pillar where you can find the only secret shell of the level.
Shadow Tundra
Secret Shell #23 – At the fifth statue (the second after the stele) climb up the ledges on its back, then its arm to reach the sword where the shell is at the tip.
Secret Shell #24 – In the area with the giant statue, after activating the chain linked to the statue’s hand ride the chain up to it and the shell is at the tip of its sword.
Secret Shell #25 – When you reach the ice slide area, stick to the right where the group of 6 statues is located to find a small cave between the first and second on the right where the shell is located.
Secret Shell #26 – After the tube in the hall with the pillars, the shell is located on the right between the third and fourth last pillar.
Secret Shell #27 – In the next area you have the ability to use boosts by picking up wisps from the lit pillars. Grab a few (you can store up to 5 at once) then go near the top of the area and look back toward the entrance left of the shark statue where there is a jellyfish jump leading to some far away platforms. Boost and use the jellyfish jump to reach the closer platform with the chest, then boost and jump to the two near the entrance where you can find the shell at the end of the farther one.
Secret Shell #28 – Use the jellyfish jump left of the previous one to reach the far doorway. Enter the area and follow the path of bones to reach the water point. The shell is inside the skull directly above the water point.
Secret Shell #29 – In the large open area where you need to activate the 2 gold bells to open the level exit, go to the big platform with the left gold bell. Go around the back where there is a stele sitting inside the chest hole of a shark statue. Jump around the left arm of the shark statue to find the shell behind it on a ledge.
Secret Shell #30 – From where you entered the area stick to the right wall through the round rock structure, then go into the rocks on the left where the shell is secret.
Secret Shell #31 – From the same location look back toward the round rock structure where there is a snow ramp to the left. Boost and jump off the ramp on top of the rock structure where you can find the shell.
Secret Shell #32 – Near the exit of the area to the right of where the vendor is sitting there is a small corridor in the ice with the shell at the back, awarding Shadow Tundra Shell Collector .
Frozen Drifts
Secret Shell #33 – Near the end of the level after activating the final water point that brings the giant castle out of the water, go around the back of the hill with the pillar to find a group of lanterns that spawn a side area.On the side area that appears after activating the lantern at the base of the sword you can find the single secret shell for the level.
Sacred River
Secret Shell #34 – From the stairs after the lanterns, turn around and jump up to the statue with the broken head. Jump across to the back of the room where the shell is on the right side of the large statue.
Secret Shell #35 – On the ramp leading up to the next set of lanterns, jump backward into the break in the wall to find the shell in a side room.
Secret Shell #36 – After activating the water point in the large circular room, ride one of the sperm whales up to the top of the room where shell is located on the ledge around the room above where you entered.
Secret Shell #37 – After activating the first water point outside and jumping up the jellyfish to the pillar, use water rails to jump across the boats to the third one where there is a small cave with the shell.
Secret Shell #38 – In the area where you pull the giant ship out of the water, toward the back of the area near the walls you can spot a boat with a rail hint near it. Boost off the boat and grind the raid toward the tower, landing on the last section of the wall. You can boost and jump again and grind to reach the shell on the raised area.
Secret Shell #39 – From the same spot with the walls look on the left side for a section of ground wrapping back toward the entrance to the area. Jump to this level and follow it back toward the entrance to find the shell at the end. You can also get back to the prior area this way if needed by jumping toward the place you dropped into the area from.
Secret Shell #40 – After raising the giant boat, jump into the back where there is an opening to find two rooms. In the opposite room from the stele, you can find the shell in a broken pot on the left side near the wall.
Secret Shell #41 – Use the half pipe at the back of the boat to jump high into the air, then use a water rail to jump on top of the building where you can find the shell.
Secret Shell #42 -Under the giant floating island, look down to the left where you can see some lanterns in front of an opening. Use the lower boat to jump down to this opening to find the shell.
Secret Shell #43 – After activating the water point on the floating island, from the central tall platform you can see a smaller floating island to the right where the vendor will be location, and then another small floating island to the left. You’ll likely need to jump on one of the Blue Whales to then grind to the floating lanterns to reach the floating island, where you can find shell in the top room.
Secret Shell #44 – Follow the bridge that has now appeared toward the entrance, but instead of going all the way up look off the right side where there is a boat on a pillar where you can spot a shell on top. Jump and water grind over to reach it.
Boiling Cavern
Secret Shell #45 – When you reach the area with the boats floating in the lava, you need to quickly jump around the back of the pillar on the left to find the shell on a small ledge.
Secret Shell #46 – After opening the first door with the water bubble, jump up the rocks on the right behind the stele and follow the path clockwise around the room, then jump across to the far ledge where the shell is located at the top.
Secret Shell #47 – In the next area with the boats floating in the lava, on the right side of the area near the stele is a boat sideways in the lava. Jump on it to reach the ledges and follow them to the right where there is a small cave with the shell.
Secret Shell #48 – Near the start of this same area to the left is a round platform, if you look past it there is a thin corridor in the rock. Quickly jump through to the back where you can find the shell.
Secret Shell #49 – In the room with the skeletons you can grind on behind the stele, you can jump up the ledge behind a statue to find the shell, awarding Boiling Cavern Shell Collector .
Secret Shell #50 – The final shell comes from the final trade level of the vendor for 5000 Astra (8550 total).
