The star, who is currently in Japan, took to Instagram to share a video of dolphins performing at a marine park.
He called on his followers to educate themselves about the 'horrible' things that happen to animals in captivity.
'Please don't support these shows'
"So I'm back in Japan, one of my favorite places in the world. One of the most beautiful, peaceful wonderful places," he wrote.
"The culture, the people, the food and cities are wow. But do you know, this happens here in Japan. Please please don't go and support these shows around the world, don't buy tickets to show your kids.
"Instead, educate them of these horrible things that have happened to the dolphins, whales, and other sea life. These beautiful creatures shouldn't suffer."
Hamilton regularly uses Instagram to promote an animal rights message. Last month, he called on his 13.1 million followers to ditch leather.
Sharing a PETA video of the leather industry, he wrote: "I woke up feeling good today, but this has just broke my spirit. This is so graphic, so barbaric. PETA how can I help stop this?"
"She's wincing from the pain of being smashed with a sledgehammer 😔 She was still moving when they stabbed her. Her skin is now out there somewhere, likely turned into a belt or jacket. Her life was worth more than a piece of clothing—please, never buy leather."