Honestly, I didn’t think our Mediterranean vacation could get much better.

The dozen of us on the trip had already swum several miles a day through astonishing turquoise waters off Kas, a remote village on Turkey’s southwest coast, where cliffs soar up from the sea, the soft air is scented with jasmine and views of the glimmering bay are downright therapeutic.

Amid a ring of seven islands earlier in the week, our group of open-water swimmers glided alongside limestone coastlines, the sunlight spangling the underwater landscape of smooth boulders and serrated pillars. We swam over marine forests swaying in the current. We crossed into the open sea, pulling rhythmically through a panorama of royal blue, a laser show of sunbeams funneling into a gleaming ring in the depth.

“It’s like swimming in the sky,” my reluctant-swimmer wife, Susan, would say later in our breezy hotel room.

Susan; our daughters, Jenna and Michaela; and I were on a weeklong adventure — a swim vacation. It is a puzzling thing to many but is slowly gaining popularity among water lovers. The tours are a tiny sliver of one of the fastest-growing segments of tourism, so-called adventure travel, which typically involves some sort of physical activity, connection with nature and cultural immersion. Think of trekking through gorilla habitats in Rwanda or kayaking down the River Kwai in Thailand — the antithesis of a package tour to Las Vegas.

Our seven-day July trip had it all.

We swam about 1.5 miles each morning and afternoon, in translucent waters under mighty peaks. We savored local dishes like the squid our hosts caught in the sea and grilled on the boat. We stroked over ancient ruins by day and danced with young Turks by night.