SapientNitro was named the airline’s digital agency of record in April last year after a competitive pitch that also included the incumbent, OgilvyOne.
Bartle Bogle Hegarty handles creative and customer loyalty work for BA, while Carat oversees media.
In November last year, the company appointed Creston Unlimited and Aquila Insight, the data analytics consultancy, to handle CRM activity.
Last month, BA took over all the advertising space in Time Out London, the city listings and lifestyle magazine, in a deal struck by Carat.
A BA spokeswoman said: "SapientNitro continue to support the BA in-house team with creative technology and international social business, as they were recruited to do.
"Where we need to, we will flex the work our retained agencies look after to best suit our marketing strategy."