We had a great day. They came to pick us up at the hotel as explained and we took a boat to get to the island where we snorkeled. Surprisingly, we were the only 2 participants, so we had the whole boat for us.
We had the chance to see different type of fish and coral. It's not the Great Barrier Reef but there was some colorful ones.
Lunch was very generous and offered a big variety.
Finally, we had a good 2h at the beach before returning by jet boat to the wharf. The beach was small but nice and I imagine it gets very crowded with every boats stopping there for lunch during the high season or week-ends. You have a free access to hammock and chairs to enjoy the view.
Special thanks to our guide. He was bilingual, very polite and generous. By being the only tourist onboard, we took the opportunity to talk with him about Vietnam's life and have a nice chat. All day long, he has been very attentive and friendly.