The travel group is inviting agencies for chemistry meetings to be held next week and is working with ISBA on the pitch. The UK incumbent, BMB, will compete for the business.
A TUI spokeswoman said: "TUI UK will enter a pan-European pitch process with TUI Group for the creative communications strategy of its TUI-aligned brands, which include Thomson in the UK. With the recent formation of the new group, there is an opportunity for more integrated campaign planning across its business, led by a single strategic creative agency.
"The successful agency will build on the single brand proposition and strapline – ‘discover your smile’ – developed in 2014 for TUI-aligned brands."
BMB has handled TUI’s UK creative account since 2007. Before that, the agency worked with First Choice, which merged with TUI.