Abandoned suitcases are becoming increasingly common at the international terminals of major Japanese airports.

Most are left by foreign tourists when they return home, who are thought to have discarded their old suitcases after transferring their souvenirs and other purchases into new suitcases they bought in Japan.

With the number of foreigners visiting Japan expected to increase as the 2020 Tokyo Olympics and Paralympics approach, airports and police are struggling to address the problem.

About 15.5 million foreign tourists use international flights each year at Narita Airport in Chiba Prefecture. Last year about 250 suitcases were found, mainly in the international departure lobby.

They are treated as lost property and given to the Chiba prefectural police station at the airport, where they are held for three months before being discarded. The owners almost never show up to claim them.

At any given time the station usually has 50 to 60 suitcases. “They’re lost property, so we can’t throw them out right away, but it’s hard to find places to store them,” the head of the station’s accounting section said.

Other airports are experiencing the same situation. Kansai Airport in Osaka Prefecture gave 258 suitcases to the prefectural police station at the airport last year, more than three times the 80 suitcases that were found in 2013.

A total of 287 suitcases were abandoned at Chubu Airport in Aichi Prefecture last year. Haneda Airport in Tokyo finds about 10 suitcases per month, and more than 100 are abandoned each year at Shin-Chitose Airport in Hokkaido.

Most of the suitcases are left in international departure lobbies, next to garbage cans and sofas or on luggage carts. Some are found tucked away in toilet stalls. The suitcases sometimes have tags in foreign languages or contain snacks from overseas.

The company that manages Haneda Airport said that abandoned suitcases became a notable issue after the airport got more flights from China in 2015. Other airports have noticed more abandoned suitcases as the number of foreign tourists has increased.

According to persons in charge of airport and local police, it seems that people buy new suitcases to take home gifts they bought in Japan, but when they find out they will be charged extra for luggage at check-in, they throw away the old ones.

The suitcases are often filled with a lot of belongings, and the ones that are locked are treated as suspicious objects.

Police and security personnel have to examine them with metal detectors or X-ray scanners to make sure they do not contain explosives or dangerous materials, which increases the workload for security staff.

“A suspicious object might be associated with terrorism, which means we’ll need more personnel to patrol the airport,” a representative of the company that manages Kansai Airport said.

In response to the problem, Chubu Airport opened a desk in its departure lobby in March that will accept a suitcase for ¥1,080 (US$9.95).

Passengers are given a paper at check-in counters telling them that abandoning a suitcase could be punishable under Japanese laws such as the Waste Management Law. However, a month since the program launched, only three people have paid to hand over a suitcase.

“We need to think of more ways to encourage passengers to dispose [of their suitcases] responsibly,” a person in charge of the matter at the airport said.