San Juan has a number of dive sites. Playa Shon Mosa is a small beach, the second one from the East on this private plantation. There are no facilities at this location, so if you want to stay longer you have to bring your own food and drinks.
Diving at this location is easy. There is a small sandy beach from which you can easily enter the water. From there it is a moderately long swim to the drop-off. Not really a drop-off because the slope is very gentle. Swimming out you can see the beach of the next dive location, Playa Manzaliña.
Going to the left you swim along a very gradual slope, at some places even horizontal. The coral density is moderate and there are some large sandy patches in between. There is an abundance of Yellow Boring Sponge. And a lot of different corals and sponges.
Be sure to pick a recognizable spot for your navigation back. Because of the very gradual slope it is easy to miss the turn back to the coast and that could mean that you end up at the next beach and that is not where your car is parked.
How to get there
Coming from the Eastern site of the island you have to go to the Western Part. Driving along the only road to this part of the island, "road to Westpunt", you drive along Plantation House "Daniel" and past the small city of "Terra Kora" till you see a sign "Soto". There you go to the left. Follow this road. You pass the entrance to "Cas Abou" and a little later you see a sign "San Juan". Slow down because you have to make a turn to the left at the red rock with the number 20 till 23 (dive site numbers).
Follow the dirt road till you see the plantation house of San Juan. Enter through the gate and drive to the right side of the plantation house. There you have to pay the entrance fee, which is currently Nafl 5.00 per car (about US$ 2.75).
Follow the dirt road. It is a winding road. It can be in bad condition in the rainy season so you better use a jeep or pick-up to get to the beach. When you reach the first split in the road you see two stones, one of which points to Shon Mosa. Follow the sign. This brings you at the second split in the road where you can choose between Playa Largo and Shon Mosa. Take the direction of Shon Mosa. This brings you a short time later at the small beach. There is a good chance that you are the only one here. Park your car and gear up.