While hovering over the reef, I watched as Ian Brown of Neptune, N.J., swam up close to John "J2" Mryczko of Morton Grove, Ill., and signaled that he wanted someone to take their picture. Getting into the just-right pose took a minute or so for the two divers, and I almost darted over to lend a hand. But then they bunched in close and hammed it up for the camera, asking for a second and third shot as well.

What you see in those underwater photos are divers at ease in Caribbean waters, among the coral and tropical fish. What's missing are the wheelchairs.

Our team of 15 disabled divers and able-bodied dive buddies trained in different parts of the country (Indiana for me), but we all traveled to Cozumel, Mexico, to dive as a group. It was my first trip with the nonprofit Diveheart organization, and I was excited to use my new skills and meet others involved in adaptive diving.

Scuba diving can test you when you're healthy and have full use of your arms and legs. For divers with disabilities, getting geared up and onto the boat, then getting around underwater, presents some challenges.

Ian and I partnered up on the first day. He'd been injured on a motorcycle while in the Air Force. A diver and fitness fanatic — even post-injury — Ian hadn't been in the open water in 10 years.

I helped him with just the last steps of getting his wet suit on. When it was time to get out of the chair and down to the boat's swimming platform, I was surprised at how strong and confident he was.

"I had the Air Force record for pull-ups," he told me.

Down at depth, using specially webbed gloves, Ian stroked hard to keep up with the group. I stayed close, but by our third dive had to intervene only occasionally.

The buddy teams were juggled on the fourth day. My new partner was Gregg Rodriquez, a Chicago-area resident and former U.S. Marine with a traumatic brain injury (TBI). For safety, Gregg dives with a full-face mask. His speech and mobility are significantly impaired, but his sense of humor is sharp and contagious. We spent a lot of time together during meals and hanging around the hotel pool. With patience, we communicated better and learned to do so underwater, too. We saw rays and sharks, turtles, big groupers, and eels. I watched divers who can't walk balance and move themselves under the sea with courage and grace. The aquatic world — its reefs and exotic life — is open to all of us. Its reduced gravity is especially therapeutic for those with spinal-cord injuries, and people like me who love diving.

And, I found that I enjoy it even more when lending a hand.

John Koons grew up in Blue Bell, Pa., and is an English teacher and diver based in Matsumoto, Japan.