Claire Rose becomes senior business development manager, while Charlotte Ireland becomes business development manager.
Rose takes on additional key accounts, as well as responsibility for managing Seabourn's general sales agents in territories such as South Africa.
She joined Seabourn three years ago, and was previously a business development manager.
Ireland, meanwhile, steps up to the role of business development manager "in recognition of her success developing new UK accounts and growing their business", said Seabourn.
She joined the line in 2020 as business development representative, and has since 2022 served as an assistant business development manager.
Seabourn has also tweaked Louise Gould's role due to her additional responsibilities setting up events and supporting the team. She is now sales operations executive.
Rose and Ireland will now report directly to director of sales Tom Andrews.
"Lynn [Narraway, Seabourn vice-president UK and EMEA] and I would really like to congratulate Claire, Charlotte and Louise for their tireless work during this year," said Andrews.
"We are both delighted to be able to publicly recognise the achievements of these very talented and hard-working individuals."
Narraway added: "I am so proud of our entire Seabourn team in the UK and Europe who have contributed so much into making 2025 such a successful year for Seabourn Voyages and Expeditions."