WONGA WONGUE, Gabon—For the past decade, an energetic conservationist has been building the foundations for a tourism industry in Gabon, where rare forest elephants stroll down the beach, hippopotamuses surf in the ocean waves and blue-faced mandrills march by the thousands through the jungle.

The challenges for Gabon’s national parks authority and its head, Lee White, include transporting clients to remote camps in a country with little infrastructure, recruiting pygmy trackers from deep within the jungle and training antipoaching units who have to battle armed hunters and illegal gold miners in one of the world’s most pristine stretches of wilderness.

Over the past decade, with the support of government and overseas philanthropists, Mr. White has transformed Gabon’s parks authority from a group with just 100 staff with a budget of $500,000 to a $30 million operation with 800 employees, 175 cars, 35 boats and a number of aircraft, including a helicopter. Tourists have begun to arrive, with visitors up by a third this year through July compared with the average over the same period in 2017 at the country’s most-popular national park for international tourists.

Mr. White’s Gabonese gambit is at the leading edge of a trend attracting a growing list of African economies: frontier-tourism products in places that visitors often more-closely associate with conflict or instability.

In recent years, a small but swelling segment of the tourism market has been drawn to places like Chad, the Democratic Republic of Congo’s Virunga National Park, which was recently closed after two British tourists were kidnapped and their ranger killed, and war-torn Central African Republic. Tour operator Thomas Cook Group PLC recently sent a delegation to Sierra Leone, which has struggled with civil war and more recently an Ebola epidemic, to discuss offering package tours.