Underwater
There are outstanding locations for snorkeling or diving. Some are even close to the shore and not a boat necessary. Share special places you know and describe what to expect.
Panama
Spain
Brazil
France
May to October, with a great start in May when a mass of cuttle fish enter the estuary to spawn
Netherlands 
May until October for diving and snorkeling June/ Juli (depending on the water temperature) until September.
Peak season July and August. Our preferred month is September, fewer crowds and less cold. Avoid the crowds at weekends. Best light from 10 a.m. until 2 p.m.
Check the weather forecast first; sometimes flood waves can happen. Weather Forecast
Switzerland