I WISH I could say that I took my tennis vacation last winter at one of those spartan camps where you sleep in a dormitory after your aching muscles give out each night and wake to the tune of warm-up drills every morning. It would make me feel self-righteous.

But I confess that the tennis improvement program I chose was laced liberally with Puerto Rican sunshine, cool Caribbean breezes and Pina Coladas served courtside every day at 5 p.m. If you're going to brush up on your backhand, this is the way to go.

And the beauty of the whole thing was that I ended up on this vacation purely by accident, with impromptu planning that took less than an afternoon.

I was actually headed for a car touring trip in Mexico when a friend, who was the guiding spirit and prospective leader for the excursion, came down with the flu. The prospect of navigating through Mexico myself, on one word of Spanish, did not exactly thrill me.

It was 10 days before Thanksgiving, I had a week off coming and suddenly no place to go. I headed for my tennis club to revive my lagging spirits, and when my tennis partner heard of my canceled plans, he suggested I spend a week at a tennis camp, which considering my performance on the courts, seemed like a good idea to everyone.

It also looked to me like the perfect vacation to take alone. Since I'd never traveled by myself, I was leery of a trip in which I'd have to make daily decisions about where to stay, where to eat and what to do. At a tennis camp, the game would provide a scheduled activity and a common interest with the people I'd meet, and there'd be restaurants and other activities available for the campers.

The place I chose, Palmas del Mar in Puerto Rico, provided all that, and more, in an atmosphere beyond anything the words tennis camp had ever conjured up in my mind. The tennis program was run by All American Sports, a company that in the past 15 years has set up tennis clinics at some of the top summer and winter resorts around the United States. With their program, you get the benefit of a full-service tennis camp -- topnotch instructors, videotape playbacks, use of ball machines and unlimited time on the courts -- in an environment that offers all the amenities a vacationer could want.

I'd heard of All American's program when I stayed at the Boar's Head Inn in Charlottesville, where the company recently set up a tennis clinic. After inquiring about it there, I started receiving their brochures, and I was able to dig one out that week when I found myself with no place to go. Their brochure offered lots of choices for a winter trip: Amelia Island Planatation in Florida, Half Mon in Jamaica and Palmas del Mar in Puerto Rico. All had the same tennis programs.

With the help of an All American employee at the company's 800 number, I picked Palmas del Mar for three reasons. The weather they said, was perfect at that time of year. They were right. Since Palmas, like many resorts, had only double rooms, single travelers normally paid close to the double rate just for themselves. However, during select times of the year, and this was one of them, singles were not charged the double rate. That meant my five-night "Tennis Plus" package cost $410 for the room and 12 hours of instruction, instead of the $505 or more that it would cost at other times of the year. Finally, Capitol Airlines offered a $190 round-trip fare from New York's Kennedy Airport to San Juan, about an hour's ride from the resort.

I also learned that Palmas had 3 1/2 miles of beach, a golf course, two pools, several restaurants and everything from sailing to horseback riding. I thought I could manage to keep busy for five days.

That was Monday. By Thursday my reservations were confirmed in a letter from All American. And on Saturday I arrived at the San Juan Airport, planning to spend one night in San Juan, gambling at the casinos, and then move on to Palmas the next day.

The next morning, about $100 poorer, I waited in the La Concha Hotel lobby for All American tennis director Carey Bradburn to pick me up for the drive out to Palmas. Normally, vacationers in the tennis program are picked up at the San Juan airport by a Palmas van when they arrive. The charge for that is $15. But All American had offered to have Bradburn meet me in San Juan, when I told them I was going there as a little one-night sidetrip. The free ride out to Palmas is not part of the program, but it's the kind of special "extra" that happened again and again during the trip. By the time we finished the hour's drive to Palmas, Bradburn seemed like an old friend.

As soon as I got to my room at the resort's Candelero Hotel, there was a note from tennis clinic director Art Jerome, inviting me to the 3 p.m. introductory class. There wasn't even time to get nervous about being alone in a strange, new environment or playing my brand of beginner's tennis in front of a bunch of people I'd never met.

I met my classmates on the courts; Lea Dann, a physician from the Bronx; Shellee Robbins, a psychologist from New York City who had been playing tennis for quite some time and was a veteran of the All American program; Martine and Patrice Folly, a French couple who had recently moved to New York City, and Ben Pacheco, who worked at Palmas and joined us for some of the lessons.

It was a genuinely international group. As we got into more difficult maneuvers, you could hear swearing on the courts in at least two different languages. "Tout le monde est mauvais," Martine shouted at the end of one session. Even though it was true -- we were all terrible that day -- somehow it sounded better in French.

Learning, in general, was better with this group: a real team spirit developed, and the goal, as Jerome explained to me, was getting everyone to play better at his or her own level. "The rule is keeping your strokes basic, and getting people to deal with their own ability," he said. Sure there was some competitive pressure, but everybody also cheered when one of us mastered a new skill.

Classes began at 8 a.m. sharp, which meant I was getting up earlier than I normally did. I won't say that part was easy, and true to form I was a few minutes late to every session.

The student group, as small as it was, was broken down further according to ability. These tiny sub-groups rotated onto a different court every half hour to work on a different stroke with a different instructor. That way you got a taste of the varied teaching styles of all the pros, who did have one thing in common, a sense of humor that became invaluable as they demanded more and more from us.

Clinic director Jerome was a master of the sarcastic comeback and he made you want to succeed if only to avoid his next tart-tongued comment. Bradburn broke things down into simple, easy-to-handle tasks and always had an encouraging word no matter how badly things were going.

Sergio Streptman had a gentle way of correcting your faults and was the man who taught me, finally, how to serve. I'd had all the basics wrong for years, despite a number of sporadic lessons. And finally, Jim Labinski, the newest member of the teaching crew, who delivered a nonstop stream of criticism and encouragement along with all his shots.

I took the five-night "Tennis Plus" program, which translates to tennis, plus lots of time for other activities. It included two hours of group lessons each day, from 8 to 10 a.m., plus two half-hour private lessons, usually scheduled for the afternoons. The "full session" program, costing about $130 more, offered four hours of tennis instruction a day from 8 a.m. to noon, plus the private lessons.

Both packages included use of the automatic ball machines and unlimited free time on the courts, which served resort guests and the owners of the condominiums and townhouses that dotted Palmas' beach and hung from the hillsides. The All American crew delivered quickly on its promise to find a tennis partner at my playing level among the club members.

With their help, I fashioned my own tennis program around the morning clinics. At 10 a.m., after class, I took a break for breakfast, or what had to pass for it. Food was not Palmas' long suit. Breakfast at the Candalero Hotel's restaurant stopped promptly at 10 a.m. Those of us who didn't want to get up at 7 a.m. to eat before class were out of luck. I made do with some fresh fruit and a box of doughnuts that I bought at a local store when I went to town for dinner one night. I'm told that during "in-season" weeks, Dec. 15 through mid-April, there are more restaurant options available. The prices are higher, too.

After breakfast, I'd work with the ball machines for an hour, usually getting some pointers from the instructors. Lunch was usually a pizza or sandwich with Bradburn or one of my classmates at the poolside restaurant. Then I'd hit the beach for the hottest part of the day. At 4 p.m., I'd return for an afternoon game with my newfound tennis partner. Though she was, indeed, a much stronger player than I, miraculously on Thursday I won several games.

The rest of my classmates took the full session and were often too tired to use their free court time. It was a trade-off. They got two more hours each day with the pros.

Every afternoon at 5, my classmates and I got some real inspiration. The pros would play an exhibition doubles match. The week I was there, the fourth player was a one-time member of the Spanish Davis Cup team, who happened to be visiting the resort. They'd play, and we'd drink Pina Coladas. I thought it was a perfect division of labor.

On two of the five nights, we went to "strategy sessions" at the Gibraltar Pub, where chili and sandwiches were served up with advice on the game. The sessions were chalk talks, which turned into comedy routines when Art Jerome was at the blackboard. Amazingly though, even a novice -- like me -- could play much better tennis when applying the rules they laid out. Their strategy for mixed doubles included some simple tips that are seldom applied in club play. I'm convinced that a couple of average players using this strategy could best superior players on the courts.

One of the advantages of the pace of the program was that you weren't too tired at night to enjoy yourself. No, I wasn't exactly ready to party till dawn, but there was really no place to do that at Palmas anyway. I'm told that changes, too, during the in-season, particularly at Christmas-time.

Our group dinners at the Pub broke up about 11 p.m. The other nights I ate at La Marina, the French restaurant at the harbor that had the best food at the resort. The hotel's Las Garzas restaurant was mediocre. One night, a few of us took an excursion into one of the nearby towns to a storefront restaurant that was great. Shellee Robbins, whose parents owned a condominium at Palmas, was familiar enough with the terrain to get us there, but it might be difficult for a first-time tourist.

Palmas offered its own excursions, including a night tour of San Juan's casinos, a day tour of Old San Juan or an afternoon at the race track. A quick hop by plane for shopping in nearby St. Thomas sounded enticing, but I was having too good a time to bother with it. Next time, I might stay a day or two extra and try some of those options.

The five days, which I stretched into a sixth by booking a late-night flight home Friday, raced by. The instruction was first-rate and besides improving our skills, the pros instilled in us a sense of humor about our shortcomings -- a real asset for a beginner in a difficult game like tennis.

On the way out to the San Juan airport with my classmate Lea Dann, a man in the van asked us if the 5-day training session had really improved our games. "Yeah," said Lea with a grin, "now when we miss the ball, we know exactly what we're doing wrong."