Unite said it will be maintaining "three strictly socially distanced picket lines".
Unite recorded an 84% yes vote among its members at Heathrow, in opposition, Unite said, to "fire and rehire policies that will result in workers suffering permanent pay cuts of up to £8,000 per annum".
The strike action will involve firefighters, engineers, campus security, baggage operations, central terminal operations, landside and airside operations.
Unite regional co-ordinating officer Wayne King said: “Unite have tried to negotiate temporary pay cuts but Heathrow were simply not interested.
