SAN FELIPE, Mexico — Rodrigo Ortega Montes was barefoot and beaming, a hammer in one hand, a bucket full of clams and sea snails in the other.

“Very rich,” he said in Spanish, meaning the snails.

We were alone on the beach. When I introduced myself, Ortega told me how he had left Mazatlan, worked in California for a few years, then found his way to a construction job here. He squinted south at the blue horizon, the knife-sharp outline of a rocky hill with the sun behind it, and raised his arms.

“All this,” he said, “and no migra.”

Whether you’re coming from the north or south — with or without immigration officials to consider — life can be grand in this corner of Baja California. But it is getting more complicated.

San Felipe, about 350 miles south and slightly east of Los Angeles, was founded in 1916 or 1925 (depending on who’s counting) as a fishing port. Once the paved road to the U.S. border went through in the early 1950s, American anglers and adventurers started coming. Now a sign puts the full-time population at 19,263, although the 2005 census places the number at 14,831.

Even with no commercial flights, the town gets as many as 250,000 American and Canadian visitors yearly, many of them snowbirds in RVs who park their vehicles in dozens of campgrounds known as campos.

During spring break season — essentially, the month of March — the city teems with college students eager to drink legally at age 18 and line up for foam parties. (If you have to ask, you’re too old.) Off-road races such as the San Felipe 250 (March 14 and 15) come up now and again.

The rule of thumb: Californians come from spring through fall, and Canadians descend in winter. And every day the sun rises over the sea and sets over the mountains.

Besides fishing, clamming, drinking and lounging, visitors roar through the desert on off-road vehicles of all kinds. For a day trip, many make the 55-mile paved drive to Puertecitos, a quirky American expat and retirement enclave with natural hot springs at the sea’s edge.

At night, you can stroll past the row of semi-rustic restaurants and bars along the malecon. At any hour, you’re likely to catch fishermen fussing with their boats. On beaches at the edge of town, you see hundreds of four-posted huts — parking ports waiting for RVs.

Arriving by road — yes, it’s paved — you reach San Felipe by miles of stark borderlands driving (with a military checkpoint or two along the way). To your right rise the serrated foothills of Baja’s Sierra San Pedro Martir range, with the usual Baja stubble of ocotillo, mesquite and scattered cardon cactus. On the left it’s all flat.

This was once a big wetlands, the estuary of the Colorado River. Now that there’s nearly nothing left of the Colorado by the time it gets here, the old delta has devolved into a dead zone, too salty even for cactus.

Rolling beyond that dead zone and into San Felipe, you sidle up to the Gulf of California, a.k.a. the Sea of Cortes. You pass a dozen or more beachfront campgrounds for RV people and owners of rustic vacation homes. The rocky slopes of 955-foot Cerro el Machorro rise at the northern end of the town and bay, and white sandy beaches march south into the distance.

Depending on when you look, the beach might seem a bit broad or downright eerie — the retreating sea can lay bare as much as a quarter-mile of damp sand.

On a low hill in the shadow of Cerro el Machorro, the Catholic faithful have put up a blue and white shrine to Our Lady of Guadalupe, a spot that offers the best view in town and is visible to boats for miles around. The two rowdiest spring-break party bars, Rockodile and the Beachcomber, stand along the malecon, the three-block street and promenade that fronts the beach.

At the northern end of the malecon, beyond the footbridge that leads to the Guadalupe shrine, stand the Lighthouse restaurant and a hulking ship-shaped discotheque called the Boom Boom Room.

Look left as you cross the foot bridge and you behold the town’s derelict old shipworks, now a wet graveyard for several vessels that will never float again. Look right for a great panorama of beach and sea, including dozens of fishing boats, whose owners typically slouch nearby, mending nets.

Meanwhile, with most of its visitors in RVs, condos or vacation homes, San Felipe sustains a strange and perplexing batch of hotels.

Beachfront El Cortez, built in 1959, is well-kept but stopped taking credit cards late in 2007. The Costa Azul stands in a prime spot at the end of the malecon, but its rooms are marred by flaking paint, and the staff doesn’t bother to open the restaurant or heat the pool off-season. The Hotel San Felipe Marina Resort &Spa, south of town, has 55 rooms within steps of the beach — but no marina or spa.

If you’re a believer in deadlines, this probably isn’t the place for you anyway. I fell in step with San Felipe when I stopped consulting my watch and meandered from meal to beach to car to meal to beach to bed, time-traveling between old and new.

For breakfast one day, I had a $5.75 eggs Benedict at Pavilion, a fancy restaurant neighboring a golf course. For dinner one night I had grilled shrimp for $11 on the upstairs patio of Conchita’s, gazing out at the sea and guessing whether the fake marlin that dangled from a wire above the family at the best table posed a safety risk.

Eventually I stopped worrying and had another beer. That, for now, is the San Felipe way.