4-Day Southern Islands: El Junco's Freshwater Crater

San Cristobal's airport sits at the edge of Puerto Baquerizo Moreno, a five-minute drive from the town center, so this is usually your first taste of the islands rather than a standalone excursion. Sea lions and marine iguanas are known to rest right next to the runway here, an unscripted welcome few airports can match. From the terminal, a short transfer takes you down to the pier for a panga ride out to your ship.

El Junco sits in the highlands of San Cristobal at around 700 meters, the flooded caldera of an extinct volcano and one of the few permanent freshwater sources anywhere in the Galapagos. A short trail circles the rim through ferns and Miconia shrubland. It's one of the best birding stops in the islands. Frigatebirds fly all the way up from the coast to bathe and drink here, a rare freshwater habit for a seabird.

A short landing on one of the most beautiful beaches in the islands brings you into a resident colony of Galapagos sea lions, sprawled across the white sand. Between August and November you may also spot pups nursing nearby. This is one of the only places to see the Espanola mockingbird, found nowhere else on Earth and famously unbothered by visitors. After time on the beach, a relaxed snorkel just offshore is a good way to close out the visit, with spotted eagle rays often gliding beneath the surface.

A dry landing among the rocks puts you right at the start of one of the richest walks in the islands. The trail follows dramatic cliffs where blowholes send spray high into the air with every swell, and along the way marine iguanas bask on the black rock. Between December and March, the males here turn a striking red and green for the breeding season. Punta Suarez is the only place on Earth where waved albatrosses nest, and between April and December you'll find the colony in full swing, their courtship displays peaking in October. Blue-footed and Nazca boobies nest along the same stretch of cliff, red-billed tropicbirds circle overhead, and the endemic Espanola mockingbird, famously bold, often comes right up to visitors. Keep an eye out too for the Galapagos hawk and the Galapagos dove working the scrub beside the trail.

From the landing, a trail leads to a wide, shallow lagoon where Galapagos flamingos wade through the shallows, filtering shrimp from the mud that gives them their color. Continuing over a low rise brings you to Flour Beach, a nesting ground for green sea turtles between December and June. Just offshore, the eroded remains of an old volcanic cone form Devil's Crown, one of the best snorkeling spots in the islands. White-tipped reef sharks and spotted eagle rays are a near-certain sight inside the ring, and on a good day you might also spot hammerhead sharks, sea lions, or a colorful mix of reef fish weaving through the rocks.

From the landing, a trail leads to a wide, shallow lagoon where Galapagos flamingos wade through the shallows, filtering shrimp from the mud that gives them their color. Continuing over a low rise brings you to Flour Beach, a nesting ground for green sea turtles between December and June. Just offshore, the eroded remains of an old volcanic cone form Devil's Crown, one of the best snorkeling spots in the islands. White-tipped reef sharks and spotted eagle rays are a near-certain sight inside the ring, and on a good day you might also spot hammerhead sharks, sea lions, or a colorful mix of reef fish weaving through the rocks.

One of the few places in the islands where human history takes center stage over wildlife. In 1793, a whaling captain installed a wooden barrel here as an informal mailbox, and the tradition has never stopped: you're welcome to leave a postcard without a stamp, and to sort through what's already inside for anything addressed near your own home to hand-deliver in person. After a wet landing on the sandy beach, a short walk brings you to the barrel. It is one of the most memorable traditions anywhere in the islands.

A scenic lookout point on Floreana overlooking the water below, where brown pelicans, red-footed boobies, magnificent frigatebirds, and the diminutive Elliot's storm-petrel are often seen over the surrounding cliffs and sea.

Despite the name, Los Gemelos aren't volcanic craters. They're twin sinkholes, formed when empty underground magma chambers collapsed, set in the misty highlands of Santa Cruz and ringed by dense, endemic Scalesia forest. A trail loops around both rims through some of the lushest vegetation in the islands, one of the better places in the archipelago to spot a short-eared owl hunting in daylight, and, with patience, the increasingly rare vermilion flycatcher.

The return transfer is straightforward: a panga ride from your ship to the pier, then a short bus ride to Baltra's airport, the world's first fully ecological terminal, run on solar and wind power. Land iguanas, reintroduced here after being wiped out decades ago, are sometimes seen right around the grounds on the way to your flight.