Retired Arkansas accountant Dora Jane Flesher wanted a postpandemic adventure off the beaten track. In Saudi Arabia she was mesmerized by ancient tombs carved into sandstone outcroppings in Al-Ula. She was less impressed by a museum featuring a collection of old TVs and touch-tone phones plus rocks from every U.S. state.

"We got to see the country at the beginning of its opening up," said Ms. Flesher, 65. "But that meant we saw a lot of random things that will not be popular tourist destinations."

Welcome to one of the world's newest tourist frontiers.

Saudi Arabia, home to Islam's holiest sites, has welcomed Muslim pilgrims for centuries, but conservative mores and wariness of outsiders have long thwarted the growth of a traditional tourism industry and turned off prospective visitors.

Now, the government plans to spend $1 trillion over the next decade to turn Saudi Arabia into a mass-market tourist destination, part of efforts to diversify its oil-dependent economy. A nascent cruise sector, luxury Red Sea resorts and eco-lodges in the desert are all in the works.

The first Western tourists are getting a more rough-and-ready experience.