James Michael Grimes fell off a Carnival Cruise ship last week off the Gulf of Mexico, however, he lives to tell his extraordinary tale.

The 28-year-old was on Carnival Valor with 18 family members, all set to celebrate Thanksgiving, when Mr Grimes went to use a restroom at around 11pm and never returned.

An estimated 20 hours later he was fished out of the water by emergency services and he credits surviving the time in between to keeping his will to survive alive and his attitude positive.

Mr Grimes told CNN: “I was trying to stay as positive as I could from the moment I came to, and regain consciousness, I can just remember right then thinking, ‘wow, it’s a miracle that I’m not already dead.”

Beyond swimming two schools of jellyfish, surviving a night in the pitch-black ocean, and losing almost 20 pounds during the experience, Mr Grimes also encountered a mysterious sea creature.

“It came up on me really quick. And I went under, and I could see it. And it wasn’t a shark, I don’t believe. But it had more like a flat mouth, and it came up and bumped one of my legs, and I kicked it with the other leg. It scared me, not knowing what it was … all I could see was a fin.”

At one point of distress he even began chewing on a floating stick he found: “It gave some type of flavor in my mouth other than saltwater.”

Mr Grimes said he was having a conversation with god while in the ocean.

“The Lord gave me the will to live. It’s a miracle. I wasn’t going to give up at any point in time and just say, this is it, this is the end. It never came to that. I was determined to swim until my arms and legs could not hold my body up anymore.”

“It wasn’t a matter of if I get saved or if they find me, it was just a matter of when, and I just got to keep swimming until they do.”

Having gone missing at 11 pm on the previous night, Mr Grimes was spotted at 8:25 pm the next night, leaving around 21 hours that he could’ve been at sea.

Mr Grimes said he won’t rule out cruising again in the future and is already planning a trip to New Orleans to thank the Coast Guard crew that saved him.

“If that’s the worst thing I ever have to go through again, I think I’ll be okay.

“Being the Alabama fan that I am, I was out there just rolling with the tide.”

Of the approximately 25 million people that cruise worldwide, only around 25 fall off the ship each year, with an average of less than four fatalities per year.