North America · Mexico
Magdalena Bay
Striped marlin lance through sardine baitballs in open ocean
Each autumn, sardines pushed south along the Baja Pacific coast are cornered on the offshore banks outside Magdalena Bay, and striped marlin arrive in the hundreds to hunt them. Boats look for birds, drop swimmers into open ocean and marlin light up and lance through baitballs a few metres away, often alongside sea lions, mahi-mahi and the occasional humpback or orca. It is a snorkelling and freediving trip, not a scuba one — bubbles scatter the bait and end the encounter.
About diving in Magdalena Bay
The trip is a search rather than a dive schedule. Boats leave from the fishing town inside the bay, run out through the mouth and then spend the day covering water, watching for working birds and for the surface disturbance that marks bait being pushed from below. When something is found, guides put swimmers in for short bursts: slide in, swim hard, climb back aboard, reposition, and repeat for as long as the action holds. Some days deliver hours of it and some deliver nothing at all.
There is no bottom reference and no site in the usual sense. Everything happens in the top few metres of open ocean, and the banks work as a search area rather than as a mark on a chart. Fitness decides how much you actually see, because the bait keeps moving and anyone who cannot cover ground in swell ends up watching from behind the action. Boats are small and open and the days are long, so seasickness and sun exposure matter as much as the water, which sits in the low to mid twenties.
Kit is minimal: a thin wetsuit, long fins, mask and snorkel, and a wide lens if you shoot. The useful preparation is swimming rather than gear, since the day is a series of sprints, and a little breath-hold work helps, because dropping two or three metres and staying still is what keeps you in the encounter rather than chasing it from the surface.
It suits confident open-water swimmers, freedivers and photographers, and works badly for anyone picturing a conventional dive holiday with a guide and a briefing. Most people book several consecutive days so the blanks average out, and many attach scuba elsewhere in Baja on either side of the trip. The bay's other trade is grey-whale watching from boats in winter, roughly January to March, a separate business with its own operators and no in-water diving attached.
When to dive Magdalena Bay
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Off-season | Off-season | Off-season | Off-season | Off-season | Off-season | Fair | Fair | Good | Prime | Prime | Good |
The baitball season runs Oct–Dec and peaks in November; outside it the marlin disperse and operators do not run trips.
Getting there
Trips stage from Puerto San Carlos on the Baja Pacific coast, reached by road in three to four hours from Loreto or La Paz, which are the usual fly-in airports. Everything runs in small open boats out through the bay mouth, and some operators keep guests aboard a larger vessel offshore instead of returning to town each night.
Wildlife calendar
Striped marlin are the target, and the hunting builds through the autumn to a peak in October and November before easing off in December. Common dolphins and sea lions often work the same bait, tuna push through it and blue sharks turn up around the edges. Whales move along the coast later in the window, and orcas appear unpredictably rather than to any schedule.
Dive types & marine life
- Pelagic & blue water
- Marlin & sailfish
- Sardine baitballs
- Seals & sea lions
- Dolphins
- Whales
- Orcas
- Tuna
- Blue & mako sharks
Notable dive sites in Magdalena Bay
Thetis Bank
Offshore bank where the sardine shoals concentrate and marlin hunt.
Punta Entrada
Mouth of the bay, first stop when the swell is too big offshore.
Isla Santa Margarita
Southern barrier island with sea lion colonies and sheltered water.
Boca de Soledad
Northern channel used for grey whale encounters later in the season.
Dive videos
Sardine Run Mexico | Baja California | Magdalena Bay | Sony A7S III · rolf kolenbrander on YouTube
Similar destinations
Habituated giant oceanic manta rays circle divers at open-water cleaning stations.
Playful sea lions and towering kelp forests around rocky island pinnacles.
Sea lion pups play with divers at Los Islotes while hammerheads school at El Bajo.
Healthy coral reef caps 100 miles offshore, famous for August coral spawning.



