That really depends on the type of turtle! Most turtles have a heartbeat of between 10 and 20 beats per minute, but this varies from species to species, and will decrease if the turtle swims deep in the ocean.
Beats Per Minute
Sea turtles usually have a heartbeat of around 20 beats per minute, but the deeper they swim, the lower their heartbeats become. In some cases, their hearts will only beat once in every nine minutes!
Hold Your Breath! These turtles spend a lot of time holding their breath underwater, and can stay there for up to five hours without needing to surface.
Big, Strong Hearts Turtles have large, powerful hearts that beat very strongly, even if they don't do so very often.
The bigger the turtle, the bigger the heart - and this is is part of the reason why some giant turtles can live for around two hundred years!