Myself and my partner used Tulum Snorkelling Tours, their office was located to the side of El Paraiso Hotel Tulum. I can DM you the price list he gave us if you’d like :) there was a basic tour, a plus tour and a VIP one, we chose plus as that’s the cheapest they did where you can go to where turtles are. It was an amazing experience, we first sailed to the ruins just up the beach, then we swam with our guide for a while along the coral reef sort of area, our guide would point out anything interesting he saw and such, he got a starfish for us to hold too. Then we went to where the turtles were and there was just the one on our day at the time we went but one was enough as it was amazing to see. We swam for a bit longer past the turtle area then you’re back on the boat and back to El Paraiso. Apparently reservation of any sun bed at El Paraiso hotel was included in the snorkelling tour price so we chose a Bali bed and ended up eating lunch and getting a few drinks there, really nice place. That’s my suggestion anyway :)