The airline is understood to have budget of a little more than £1m a year to spend on international agency support.
Last year, BA retained the three incumbents of its international roster - Grayling for Europe and APAC, Meropa in Africa and Action in the Middle East.
BA is now sending an initial RFI asking agencies to specify which region or regions they might cover. The airline could appoint one agency globally or multiple to cover different geographies. An RFP will follow, with a view to new contracts being in place by January.
In addition to the geographies covered by the agencies named above, BA is seeking support in the Americas. UK PR is handled in-house.
The review is being handled by head of global PR Kathryn Williamson.
Agencies taking part in the process may also have the chance to become involved in other companies within International Airlines Group; these include Aer Lingus, Iberia and Vueling.
Earlier this year, BA merged its international and UK PR teams last year to create a single, global PR structure within its London HQ.
In May, the airline's marketing team awarded a creative, media, social media and paid search brief to WPP. Michael Frohlich, EMEA CEO of Ogilvy PR, is understood to by leading on elements of the brief.
BA has been subject to criticism for its comms and customer service reactions to an IT meltdown in May, and has suffered other disruption in recent months - but is also on the shortlist for the PRWeek UK Awards, which will be handed out next week.