Oysters are a collectible that span the entirety of San Andreas and can be found underwater. Because of this, you will need to dive in order to find them, which means that there might be some instances where your Lung Capacity isn’t quite up to snuff to get a particular one. However, increase it enough and you should be able to nab all of the Oysters. For collecting all 50 of them, you will obtain $100,000, as well as increase your Lung Capacity to the max. In addition to this, you can begin dating any of the Girlfriends in the game, without having to worry about your appearance or Sex Appeal. Note that this doesn’t affect the normal female pedestrians in the game.
Let’s start with the eastern side of Los Santos, southeast of the stadium. Find the pier that sticks out on your end from the beach in Playa Del Seville. The oyster is at the end of pier, in the water.
Go south to the island section of Ocean Docks. On the south side is a dock just to the west of the ship on the easternmost side. The oyster is right next to the docking area.
Swim west from the last one and find the little inlet. Look up and find the bridge that passes over this inlet. The oyster is underneath this bridge.
Swim west again to find the southernmost bridge that connects Ocean Docks to Los Santos International. The oyster is under this bridge.
Get back on land and head to the beach just south of Los Santos International. Follow it west until it starts to curve north. The Oyster will be in the water at the bend in the terrain, on your map. This can be an annoying one to find, as there’s nothing that really stands out as a landmark.
Swim along the coast north until you get to Verdant Bluffs. Find where the road begins to enter a tunnel. The oyster is located near the beginning of the tunnel near the cliff.
Continue up to Verona Beach and find the two pedestrian bridges just west of the long pier. The oyster is under the north one.
Go west to Santa Maria Beach and find the lighthouse to the left of the long pier. The oyster is just south of the lighthouse.
Go just north of Verona Beach to find Marina. There should be a small river-like waterway a bit to the west of the burger place. Find the northernmost bridge and you’ll find the oyster underneath it.
Now, head all the way to Glen Park, to the actual park you should have noticed in a few missions involving gang territories. You should find the oyster in the pond in the middle of the park, underneath the overpass.
Go to Madd Dogg’s house in Mulholland and find the pool. Note that this is the smae house you snuck into whenever you did the mission, Madd Dogg’s Rhymes. The oyster is in the pool.
Next, go to the northwest and find the town of Blueberry. Follow the middle road east out of the town, to the first intersection, then south and you should find two bridges, one wooden and one concrete. The oyster is underneath them.
Follow this river east until you get to Fisher’s Lagoon. There is a pier jutting from the east beach here. The oyster is at the end of the pier.
Swim to the north, following the water, to the second bridge just before the freeway overpass. The oyster is under the second bridge.
Head to the Federick Bridge on the right side of Los Santos, which connects to Las Venturas (it’s a train bridge). Not including the support beam at the beginning, the oyster is on the north side of the third beam. Note that this won’t be far enough to trigger the Wanted Levels if you haven’t unlocked Las Venturas yet.