In April, Mr. Putin announced that he had ordered the price of round-trip airplane tickets for vacationers from Russia slashed to $214, compared with a normal fare of about $385 from Moscow, and subsidized train tickets. State-run companies like Gazprom and Rosneft said they would underwrite vacations for tens of thousands of employees.

Some Russians who work for government-owned companies have told their friends that they were ordered to vacation in Crimea this year. State-run television inaugurated a relentless campaign plugging the peninsula: Caves! Waterfalls! Palaces! Yuri Gagarin vacationed here! (Gagarin, the first man in space, remains a Russian archetype, used to plug almost any state goal.)

But even Mr. Putin spoke bluntly about the limits of its attractions.

“If we don’t offer cheap tickets, people simply won’t go,” he said in announcing the subsidies. “Given its current infrastructure, Crimea is designed for people with small incomes.”

Sunshine, agriculture and the dilapidated Black Sea fleet are the three main pillars the Kremlin expects to exploit in its push to transform Crimea into an economic success story that proves the benefits of Mother Russia’s embrace. There has also been talk of casinos.

Propping up Crimea will be a difficult, expensive effort. Russia has earmarked $5 billion just to save the Black Sea fleet from the scrap heap. Agricultural exports face transportation issues because the peninsula is geographically remote from Russia.

But tourism presents some of the biggest challenges. After being the playground of royalty, Crimea remained a cherished summer vacation destination in the Soviet Union, as few Soviets were allowed to travel abroad. It offered some of the only warm beaches available. So tourism has long been a cornerstone of the economy.