ISLA SAN MARCOS SOUTH
Thursday, November 6, 2022
27º 10.778 N, 112º 04.052 W
A Touch of the Moon in the Sea of Cortez: Isla San Marcos
The first time I heard about Isla San Marcos, I pictured a quiet, uninhabited island in the middle of the Sea of Cortez. Turns out, it’s actually home to a gypsum mining operation, which gives part of the island an almost lunar appearance. Still, the south anchorage is a world away from any industrial activity. The moment we dropped anchor here, I could tell we’d found a pleasing balance—an isolated cove with a glimpse of Baja’s more practical side.
We’d sailed out of Santa Rosalia early in the morning. The wind was steady at about 12 knots from the north, offering us a comfortable beam reach. I took the helm, while George handled sail trim and occasionally teased out a hand line off Thaalia’s stern. By midday, the breeze mellowed, and the sun hung almost directly overhead, heating everything in sight. We ended up motor sailing the last hour, arriving at Isla San Marcos just as the afternoon light began to shift.
Dropping the anchor in about 18 feet of clear water, I noticed the seabed transition from sand to patches of seagrass. George signaled me to slow down, and soon we felt that familiar, gentle tug when the anchor grabbed. The engine rumbled to a stop, leaving us in near silence with only the slosh of small waves. That’s my favorite moment—the hush when life on the water takes center stage.
Naturally, the first thing we did was mix our “rum and yellow shit.” George raised his cup in a toast. “Here’s to another new anchorage,” he said, and clinked my glass with his. During our entire cruise this summer, we never skip that tradition. We like to think it brings us good luck, or maybe we just like any excuse for a cocktail!
The backdrop here is intriguing—one side of the island has white gypsum cliffs that catch the sunlight and shimmer in the distance, while the south side is more rugged, dotted with cacti and rocky beaches. We can see a faint line of buildings and conveyor belts on the northern part of the island, but it’s far enough away that we still feel a sense of seclusion. Occasionally, a mining barge or supply boat appears on the horizon, but they don’t come near this anchorage.
The afternoon heat was intense, hovering near the mid-90s, which is typical for early November in the central Sea. You’d think it would cool down by now, but Baja sometimes follows its own rules. Thankfully, a gentle breeze flowed later that evening, allowing us to sit comfortably in the cockpit. As the sun set, the gypsum cliffs far off turned pinkish-orange, and the water around Thaalia shimmered gold and seafoam green.
When I dipped my toes over the side, the water was warm, almost like bathwater. I jumped in for a quick swim, making a mental note to watch for any strong currents. Nearby, I saw small schools of fish darting away whenever I splashed. I’d hoped to catch a glimpse of something bigger—maybe a golden dorado or even a spotted eagle ray—but luck wasn’t with me this time. No matter; floating beside Thaalia, gazing at the horizon, was enough to chase away any lingering tiredness from yesterday’s sail.
I climbed back aboard, and darkness fell quickly, and with it came a sky full of stars. It always astonishes me how brilliant the Milky Way appears once the sun is gone and we’re away from the glow of big towns.
An interesting thing happened after dinner: I heard a low rumble in the distance. Concerned about potential chubascos (since we’ve had a few this season), we checked our weather updates on the VHF. Nothing major was forecast, but the southwestern sky did look a bit ominous with distant lightning. Thankfully, it skirted well south of us, leaving only a gentle breeze and the occasional far-off flash. It served as a reminder that the Sea of Cortez can be unpredictable, even in November.
The next morning, we woke with the sun, greeted by the calls of seabirds. George whipped up some coffee in the galley - he is often up before me. Lucky me I get coffee brought to me many a morning. Over coffee, George and I discussed our travel plans back home. We decided we both could use another day of rest.
I jumped into the water for a quick swim near the boat, coaxing George in as well. After we both cooled off, we decided to put up our shade covers and read for a bit in the cockpit.
Later that afternoon, the wind picked up from the southeast, offering relief from the heat. George put out the hand line again, but still no bites. I joked that maybe the fish went on strike. Maybe they prefer the deeper waters on the island’s north side. Regardless, it was no biggie; we had enough pasta and canned marinara sauce for a quick dinner. Not quite as exciting as fresh dorado, but hey, you can’t have everything.
We ended the evening once again with that mesmerizing Sea of Cortez sunset. A few seagulls flew overhead, heading to their nightly roosts, and the color of the cliffs shifted from white to a soft peach, then finally to a dusky pink before fading into darkness. We lingered outside, watching as the stars emerged. One of my favorite novelties out here is seeing stars reflected on the water’s surface on a calm evening, like a second sky under Thaalia’s keel.
Isla San Marcos might not have the postcard-perfect beaches of more tropical islands, but it carries a certain rugged charm. The blend of industrial history and wild Baja desert is fascinating, and the shelter of its coves gives cruisers like us a comfortable place to rest. We plan to stay another day, maybe two, before continuing south toward our next anchorage.
I sat there thinking about our trip so far. We’ve weathered chubascos, shared hikes with friends, celebrated my birthday in simpler but more meaningful ways than ever before, and caught enough dorado for countless meals. It’s the kind of life that constantly teeters between hard work and incredible rewards, between moments of solitude and bursts of communal laughter when we meet fellow cruisers.
As the sun sets, I sip the last of my rum and yellow concoction, letting my gaze wander over the silent white cliffs in the distance. I think about the subtle footprints of mining and human activity, balanced by the raw power of nature all around us. It’s a dance that’s been going on for decades, even centuries. And here we are, a small sailboat riding gentle waves in the midst of it all. With the anchor snug and the wind calm, I drift off easily that night to the lullaby of water against the hull. Tomorrow, we might snorkel close to the shoreline— I hear there’s decent visibility and pockets of fish if you know where to look. Or maybe we’ll just enjoy a lazy day onboard. Either way, Isla San Marcos has given us a memorable, offbeat taste of Baja’s multifaceted identity—desert, industry, serenity, and the ever-present wonder of life on the water.