The hotel chain will collaborate with wireless service provider STSN to offer the service in hotel lobbies, meeting rooms, restaurants and other public spaces, complementing its existing in-room high-speed access.
STSN will deliver dual-band 802.11a and 802.11b wireless access in the hotels and expects to complete the deployment by June.
Marriott is just one of many large hotel chains jumping on the WLAN bandwagon to generate additional revenue.
German hotel chain Maritim has forged a partnership with T-Mobile Deutschland to provide coverage in its hotels early next year.
For the service, T-Mobile will charge €7.95 (£5.08) for one hour, €15.95 for three hours and €24.95 for 24 hours. Customers can have the fee put on their T-Mobile invoice or pay by credit card.
The deal is in line with T-Mobile's strategy to craft WLAN deals with large chains as opposed to individual businesses. "It's nice to talk with a big hotel but it's better to talk with big hotel chains," said T-Mobile manager of data services Carsten Otto.
T-Mobile is one of the largest providers of WLAN access in the US, where it is rolling out service in some 1,200 Starbucks coffee houses.
T-Mobile also plans to add high-speed wireless Internet connectivity in about 100 US airport clubs and lounges over the next year.