They're sharing ideas about beacon technology, video analytics and other applications to deliver personalised content for passengers on their phones.
Gatwick's CIO Michael Ibbitson told CBR: "London City and Gatwick have similar shareholders so we obviously work close with them. In fact, last week I had a meeting about beacon technology with London City because they've done some really interesting things. We don't unify IT but we do share ideas and other trials."
He added: "Some of the things they've trialled are really interesting and we'll probably implement some of them here at Gatwick, and some of the ideas that we've implemented, we would imagine they would implement at London City."
He said they are currently looking closely at how passengers could take advantage of beacon technology, which delivers discounts, promotions and other alerts to smartphones as users walk past stores and restaurants.
"I know London City has done some things in this space having some apps and trialling some beacons and looking at CCTV video analytics and how that feeds in." he said.
The collaboration comes as Gatwick embarks on the refurbishment of its North Terminal, which has 14 main IT systems.
"We're intending to bring out a transformation in the way that you check in bag drop with the aim being that we want to eliminate check-in and bag drop queues completely from the airport," said Ibbitson.
The airport also signed a contract with Getronics this week for staffing services for a broad range of IT projects across the airport.
Under the four-year contract, Getronics will provide staff to fill 21 ICT roles, from service management to senior business analysts.