I have been on 2 liveaboards (to Cocos last month on Okeanos Aggressor 1 & to Socorro last week on Nautilus Belle Amie). They followed the COVID-19 protocols while we were on the boat. We were all PCR tested negative. I felt I was in a COVID-19 free environment while in the boats. I won’t feel the same if I were in a day-boat, where everyone packed together and without knowing whether divers besides me were COVID-19 free or not.
Costa Rica does not require you to have negative PCR test, unless you go to Cocos, then you need to get negative PCR test within 7 days before boarding the boat. That test costed me $130/swab. So, I and the other guests and especially the crews wanted to make sure we would be COVID-19 free during the trip. Our body temperatures were measured everyday. For the first few days I made sure to wear mask whenever social distancing wasn’t possible. Actually I felt less safe when I arrived in IAH. An overweight guy, in front of me, while waiting in line to go through the Global Entry immigration booth, turned around and started to talk to me with his mask on his chin.
Mexico also does not require you to have negative COVID-19 test, however Nautilus required you to get negative PCR test within 7 days before boarding. In addition to that, Nautilus gave me a body temperature log sheet that I required to fill out twice a day for 7 days prior to boarding. While on the boat, they continually measured everyone (the crew and the guest) body temperatures and recorded the numbers on a log sheet.
When it came to the meal time, they controlled the number of guests in the dining room by dividing us into 2 groups of 10 guests, so we can spread out while eating. Group 1 would eat first for 45 minutes, then was asked to vacate the room so group 2 could get their turn to eat. The meals were served by the waiters. No buffet.