While Jamaica struggles this summer on the long road back to touristic health, the U.S. Virgin Islands are feeling a little pain but still smiling and hoping for the best.

On St. Thomas, St. Croix and St. John, the message is clear: Hotel and restaurant business has dropped by about 40 percent since the close of the Caribbean winter high season in mid-April, a greater decline than for the same period in recent years.

Even "The American Paradise" -- as the Virgins proudly bill themselves on island license plates, signs and posters -- must now reckon with the economic realities of inflation, ever-rising costs of goods and services and a shortage of discretionary dollars for vacation spending by more cautious "statesiders."

Viewed from the capital of this U.S. Caribbean outpost, the Virgins would seem to have everything going for them. This year, well over one million travelers are expected to vacation here. Since 85 percent of those visitors will be from the United States, the rest from Europe, Canada and Central and South America, and their stay on the islands can mean as much as an additional $300 million in vitally needed revenues.

Tourism is the islands' leading industry, accounting for an estimated 35 percent of all economic activity. When the Caribbean Tourism Association ranked 20 travel destinations in the area on "attractiveness, friendliness, cleanliness, popularity and safety," the U.S. Virgins placed first in all categories. Political stability has played a major role in making these islands a long-favored tourist attraction, and the occasional outbreaks of crime in the recent past cannot be compared with the violence that shattered Jamaica.

The lack of nonstop flights to the islands, other than from Miami, and the currently inconvenient schedule of interisland commuter flights, combined with a steady rise in air fares, are a major cause of the drop in the number of passengers arriving by air, according to James Pobicki, director of policy planning and research for the Virgin Islands Department of Commerce.

In addition, the cruise ship business, which has been on the upswing here for the past four years, may be sailing into rougher waters. Pobicki forsees a 3 to 4 percent drop in passengers arriving by sea during the winter cruise season.

Hoteliers are "holding down prices through this year and the 1981-82 winter season," says Betty Sperber, of the moderately priced ($30-$45 single, $35-$55 double, summer/fall season) King Christian Hotel at Christiansted, St. Croix. "It's a big problem because fuel prices increase regardless, and we have a minimum wage law, and all other expenses continue to grow at their normal inflationary level. But because we're in the Caribbean, we have to compete with others. Haiti pays $1.80 a day for their help and we pay $3.55 an hour," she pointed out.

Pat Venckus, sales manager for the Virgin Isle Hotel ($48 single, $63 double, summer/fall rates) overlooking Charlotte Amalie harbor, looks at another side of competition: "The only problem that I see right now is our air fare, and I think we got a lot of cooperation in the past six months from the airlines . . . We had one [Capital Airlines] come into San Juan and offer a very low fare for the off season. That started competitive ratelowering between Eastern and American airlines. I think the market today is looking for that competitive spirit and travelers will shift their vacation to the area that's happening in.

"Our hotel is going back to the 'mom and pop' operation," Venckus says, "sharing secretaries, cutting labor costs. We're taking a hard look at labor. We can't cut out power or our food costs, but our service won't suffer because management is now taking a more active role."

Other changes are taking place. St. Croix airport is undergoing modernization. And by 1983, St. Thomas should have a new facility capable of handling wide-bodied aircraft.

Then there's Leona Bryant, energetic new director of the U.S. Virgin Islands Division of Tourism. Bryant, the first native-born person to hold the director's position, is currently developing an ambitious Caribbean Cultural Program. Starting with the winter season, 30 to 50 young people, ages 15 to 21, will offer island visitors a program of native dancing and singing; the intent is eventually to publicize the Virgins on tours abroad.

In still another tourism initiative, high school students on St. Thomas and St. Croix will be trained under a comprehensive study program in economics, conservation, architecture and cultural heritage to serve as guides on walking tours. A hotline (809) 773-4470 operates 24 hours a day to provide answers to tourists' questions and handle complaints.

These are hopeful signs for visitors and Virgin Islanders alike.