The first rebranded Swallow hotel will open under the Marriott name on June 5 as part of a £12m renovation programme across the whole group.
The Regents Plaza Swallow is being renamed the London Marriott Hotel West Hampstead when it reopens.
The changes follow the acquisition of the 38-strong Swallow group by Whitbread last year. Nine of the 38 Swallow Hotels are being sold off following a review.
Of the remaining properties, 21 will be rebranded Marriott, two will be named Courtyards and two will be rebranded Renaissance. Four have yet to be named.
Whitbread said it plans to double the number of Marriott hotels in the UK following the rebranding exercise.