A scuba diver in Russia got so lonely out in the ocean that he wanted his dog to come too!
So he built Boniface a diving suit of his own.
After training in a swimming pool, the diving dog has taken his first two metre plunge in the sea.
Although it might look like fun, animal charity the RSPCA has told Newsround that it's worried about someone putting an animal underwater.
So remember - DON'T try this with your own pet.