Colin Sutton and Cameron Dietrich were diving off the coast of Mexico when they found a sea turtle tangled up in the rope attached to a buoy. Though the impressive turtle is nearly as large as the divers, he was unable to free himself and the two men spent quite some time removing the rope from his fin, allowing him to swim away without a scratch.

But before he swam out of sight, the creatures turned around and surprised his rescuer with a sweet show of gratitude. Watch the video and see for yourself — who knew turtles could say “thank you”?

Sadly, rope entanglements are relatively common this time of year as sea turtles swim up north to hunt jellyfish during the summer months. Late last June, an 800 pound turtle was caught in Long Island, and scientists from the Riverhead Foundation for Marine Research and Preservation set him free. If you ever find a sea turtle caught in marine litter, call the U.S. Coast Guard for help.