Justin and Crystal Reynolds shared their first dance as husband and wife surrounded by friends, family, manta rays and whale sharks. They married while submerged in 6.3 million gallons of water inside the Ocean Voyager exhibit at the Georgia Aquarium in Atlanta.

“We definitely wanted to mix our wedding with diving because it was something we were so passionate about,” said Crystal Reynolds, 33, who lives in Weston, Fla.

In preparation for the wedding, which was three years ago, the bridesmaid, groomsman and officiant achieved scuba certification. “Everyone had to wear a dive suit, and then, over the dive suit, we wore our wedding attire,” she said. “My dress and my veil were weighted to keep them from flowing in the water.”

Justin Reynolds, 33, director of facilities at the Phillip and Patricia Frost Museum of Science in Miami, his groomsman and the officiant sported tuxedo shirts, cummerbunds and bow ties.

Following the aquatic ceremony, which cost nearly $15,000, lasted 40 minutes and included catered appetizers by Wolfgang Puck, the newlyweds changed clothes and celebrated with a private reception in the Georgia Aquarium’s Oceans Ballroom. The underwater union was the first for the aquarium, but it hosts weddings and events in other spaces on site.

Many more places not readily associated with weddings are opening their doors to couples looking to embrace the unconventional. These brides and grooms are seeking out spaces where they feel a personal connection.

“There are people who want to do something totally different and unique,” said Jen Campbell, founder and creative director of Green Wedding Shoes, a website that profiles weddings from all over the world. “People are getting married older. They’ve already been to a lot of weddings. They want to do something different, so it feels special and unique to them.”

The Green Wedding Shoes archive shares a range of matrimonial celebrations, including ceremonies and parties in airport hangars, bowling alleys, railroad museums, castles and outdoor spaces such as national parks.

“They look for something that isn’t your typical wedding venue,” said Campbell, who lives in Los Angeles.

So many couples have requested weddings at the West Coast chain Voodoo Doughnut that the company offers wedding packages with bride and groom custom doughnuts, a doughnut heart centerpiece and coffee for as many as 60 guests.

Voodoo Doughnut’s first on-site wedding ceremony was in 2003 in Portland, and since then, more than 1,000 couples have been married at the company’s stores.

“We did our first wedding at Voodoo within a couple weeks of opening,” said Kenneth Pogson, a founder of the company. Valentine’s Day, April Fools’ Day and Halloween are especially popular.

Beyond fried dough festivities, couples have devoted themselves to each other, for better or for worse, at amusement parks, Taco Bell, Costco outlets and Whole Foods Market stores, in part because they feel strong ties to these brands and businesses.

At Taco Bell’s flagship Cantina restaurant in Las Vegas, “marriage is on the menu,” according to Cantina’s wedding website, ­tacobellwedding.com. Fans of the fast-food chain — maybe those with fond date-night memories — can mark their unions in the presence of up to 25 guests.

Within the restaurant’s chapel — yes, it has a chapel — each celebration involves a 30-minute ceremony with an officiant provided and a sauce packet bouquet for the bride to hold while walking down the aisle. A reception is held within the restaurant and swag is provided, including “Just Married” T-shirts, champagne flutes and a “Taco 12 Pack.”

The first step to setting up a unique wedding venue is to pop the question.

“We didn’t even think it was possible,” Crystal Reynolds said of her underwater, aquarium wedding. “We lived in Georgia at the time, and we just kind of reached out to them on a prayer just thinking, ‘Hey, you know, what could happen? The worst they could say is no.’ ”