Life in Los Cabos is hopping.

Hotels, condominiums, golf courses, roads, restaurants and shops are popping up everywhere. Tile roofs create a ribbon of red above the blue sea, poking out all along the 22-mile corridor between the quaint, quiet, older town of San Jose del Cabo and the newer, action-packed Cabo San Lucas.There was not much more than empty beaches and barren desert along this strip only a few years ago. "Se Vende" (for sale) signs stand on vacant lots under the sun next to tall green cactuses.

This is the ends of the Earth, literally. Los Cabos - it means "the capes" and refers to the two towns of San Jose Del Cabo and Cabo San Lucas - is at the tip of land's end on the 1,000-mile-long Baja California peninsula, where the Pacific Ocean meets the Sea of Cortez (also known as the Gulf of California). It also can be the ends of the Earth figuratively. Here, at land's end, begins an enchanting experience for many.

Los Cabos is one of five Mexico resort areas targeted for expansion by Fonatur, the government agency that promotes tourism development and helps finance construction. Part of the idea is to bring the state of Baja California Sur into the mainstream of Mexico, since the peninsula is separated from the rest of the country by the sea. The potential for tourism makes development feasible.

Projects under way and in the planning stages will put Los Cabos, long known to game-fishing enthusiasts, on the tourist map. They include an airport expansion to bring more flights and accommodate jumbo DC-10s and 747s, as well as widening the corridor highway between the airport and Cabo San Lucas from two lanes to four lanes, a $44 million project.

And Conrad Hilton has broken ground along the corridor at Cabo Real for a five-star hotel to open in late 1992.

"Once the Conrad Hilton is open, other hotels - Marriott, Hyatt and Sheraton - will come in here," says Ignacio Lopez Bancalari, regional director of Fonatur. "For many years the hotels here have been family operated, basically 50- to 60-room hotels. We're approaching a different scale."

But this will not be another Cancun (also a Fonatur inspiration).

"We hope to keep the scale down. We are not letting the area just boom. We won't let it backfire on us," says Bancalari.

To a certain extent, growth of the area is limited because of lack of water. The annual rainfall amounts to an average of 12 inches, which for now replenishes the underground reservoirs from which the water supply is obtained.

"The government has to be very strict to remain within the master plan," he adds. "We have to retain the charm of the area."

By the year 2000, Fonatur projects the Los Cabos population will double to about 100,000, and will grow to 240,000 by 2030. There are about 45,000 people now.

Fonatur's master plan calls for a total of 12,000 hotel rooms (including 4,000 condominium units with hotel operations), more than four times the number now - 2,600 existing, plus 1,000 under construction. By 2000, Fonatur projects Los Cabos will have 8,000 rooms.

Big plans also are on the drawing boards for golfers. Fonatur expects to break ground next year for an 18-hole course that would open in 1994 and complement its existing nine-hole course along the corridor near Howard Johnson Plaza Suites. Hotel Palmilla, along the corridor, has signed a letter of intent with Jack Nicklaus to create a 27-hole course and companion 18-hole putting course as part of its 900-acre Palmilla Golf & Tennis Resort project, which will turn the 72-room hotel into a 200-room Four Seasons-caliber retreat. And work is under way on another 18-hole course at Conrad Hilton's Cabo Real project. Another one or two courses are expected to get under way within five years.

"We will become an important golf destination by Mexican resort standards," says Bancalari.

Luis Klein, director of the Los Cabos Tourism Board, is even more emphatic.

"We will be the golf destination of Mexico within 1 1/2 years. We will have signature holes by the ocean like Pebble Beach."

Klein, long active in the tourism industry, began his career as a hotel bellboy in Mexico City in 1968. He came to the Los Cabos area in 1980 to open Hotel Presidente, Fonatur's first project in San Jose del Cabo, and, in 1983, started Damiana's, San Jose's best restaurant, bar none. He understandably likes the changes in Los Cabos.

"We still have our pristine beauty," he says. "Now we can find beauty with a lot of amenities. We are monitoring things very carefully and everything has to have an environmental impact study. ... We have a unique combination of desert and sea. It's like a Palm Springs with ocean."

The so-called beautiful people - including Bing Crosby, Frank Sinatra, Desi Arnaz, John Wayne and Dwight Eisenhower - discovered this tip of Baja in the 1940s and 1950s. It was the domain of well-heeled sports-fishing enthusiasts who arrived by yachts or landed their private planes on a dirt strip. The area, nicknamed "Marlin Alley," attracted big names to the waters with their big-game trophies, such as marlin, tuna, dorado and wahoo.

The first hotel, Palmilla, opened in 1956 essentially as a club for sportsmen. During the next 20 years, other hotels and homes were built, along with an international airport and transpeninsular highway that runs to the Baja tip from San Diego-Tijuana. The area has become popular particularly with Southern Californians who find it close and easy to reach.

Visitors will find two sides to Los Cabos: the quiet side (San Jose del Cabo) and the rowdier side (Cabo San Lucas). The two don't compete with each other.

San Jose, a charming, more-authentically Mexican town eight miles south of the airport, is definitely laid back. Founded in 1730 as a Jesuit mission, it has colonial architecture and a typically south-of-the-border shaded main square with church, bandstand/gazebo and benches where locals gather to gossip and read newspapers. Several clothing boutiques sell top Mexican fashion designs, while a number of awning-covered sidewalk stands carry ceramics, rugs, souvenir-quality jewelry and other mementos.

If you want a more peaceful environment still, stroll about a mile to the lagoon and estuary next to Stouffer Presidente Hotel. It's a preserve filled with more than 200 species of birds and surrounded by serene marshes.

Meanwhile, down in Cabo San Lucas, it's another story, although you can find peace and quiet if you make the effort. But sooner or later you at least have to stop by some of the popular hangouts to see what they're all about - the hottest nightspot in town, Van Halen's Cabo Wabo Cantina, where you might find the likes of the Grateful Dead's Bob Weir, Don Dokken's Band, Ratt's Robbin Crosby and the BulletBoys; EL Squid Roe (a Carlos & Charlie's operation), where a hodgepodge of signs proclaims profundities such as Hemingway (never) Ate Here and Sorry, We're Open.

Look for whales while you sip margaritas at Hotel Finisterra's Whale Watcher Bar perched atop cliffs above the ocean - although we saw a pod of gray whales as we drove along the corridor highway.

Take a glass-bottom boat or sailboat to Playa de Amor (Lover's Beach), and sail past the magnificent, mysterious El Arco (The Arch), which marks land's end where the Sea of Cortez meets the Pacific.

And, late in the day, sit by the dock of the bay, along with dozens of eager pelicans, waiting for fishing fanatics to return from a day's outing with their catches, or at least with flags on their boats that indicate they made catches. Los Cabos has a catch-and-release policy that encourages visitors to tag and release their fish if they don't intend to eat them.

You'll be asked over and over: Want a fishing boat my friend? Condominium and time-share sales people will stop you on the streets to invite you to lunch, trying to convince you that there is indeed such a thing as a free meal. Meanwhile, a man with a bright-green iguana draped over his shoulder will let you take his picture for $1. For $2, you can hold the iguana and he'll take your picture (I'll pay him $2 for me not to hold the iguana).

These eager entrepreneurs are a sign of the times of Los Cabos. Along with beach vendors and Benetton, they signify that Los Cabos has arrived. It's headed for the big time.