Customers of T-Mobile US visiting Singapore over the next month will be able to connect to the Asian country's free public wireless network, Wireless@SG, via their SIM devices.

The new access option is part of a month-long trial led by local industry regulator, Infocomm Development Authority of Singapore (IDA), that also involves Land Transport Authority (LTA), Sentosa Development Corporation (SDC), as well as local telcos M1 and Singtel. T-Mobile is among preferred US data roaming partners for both Singapore telcos.

The login feature taps the user's SIM card as the credential, performing a one-time setup on the mobile device before automatically connecting to Wireless@SG. Registration is not required.

The pilot would involve some 290 hotspots at designated test areas, specifically, major MRT stations and Sentosa. Hotspots at the six participating train stations, including Orchard and Chinatown, were supported by Singtel.

Singapore's southern island resort, Sentosa in May had started a year-long trial using solar energy to power outdoor public Wi-Fi hotspots on the island. IDA then said the deployment if determined to be feasible, would be extended to other parts of Singapore and support Wireless@SG. M1 was part of the Sentosa pilot.

According to IDA, the T-Mobile trial would take place in conjunction with the Wireless Broadband Alliance City Wi-Fi Roaming Project, which also allowed Singaporeans visiting San Jose, San Francisco, and New York to roam automatically between free public Wi-Fi hotspots in the US cities.

To access this service, also available during the one-month trial, Singapore mobile users would have to download a configuration file and perform a one-time setup to initiate automatic connection to participating hotspots across the three US cities.

IDA Assistant Chief Executive Khoong Hock Yun said: "Wi-Fi is fast becoming a daily necessity and Wireless@SG, as the largest city-wide federated Wi-Fi network, will be an important enabler to improve connectivity and liveability in Singapore as we move towards a smart nation.

"Trialling the SIM-login method for foreign visitors is something new to us, and we hope to gather new insights, fine-tune technical challenges, and enhance the Wireless@SG programme further," Khoong said.