The 1,400 workers – who are based at Heathrow’s Terminal 5 and in campus security – will be striking on 4, 5, 6, 9 and 10 May and then again on 25, 26, 27 May.
The move comes after new Unite research claimed security officers at the London airport are paid £6,000 per year less than their counterparts at other local airports.
Unite general secretary Sharon Graham said: "Heathrow prides itself on being the UK’s premium airport – it is bigger and handles more flights and cargo than any other.
"So it is, frankly, indefensible that security officer pay is far lower than other London airports."
Unite research also established that since 2017, the average remuneration for Heathrow employees has fallen by 24% in real terms.
Unite regional co-ordinating officer Wayne King added: "Unite has given Heathrow airport every opportunity to make an improved pay offer, which could have led to the strike action being suspended."
Last month, Heathrow reassured passengers operations will continue to "run smoothly" this weekend despite the strike action.
As of Thursday morning (4 May), Heathrow reports the airport is "operating as usual" with security checkpoints "free-flowing". No flights have yet been cancelled as a result of the industrial action.
A Heathrow spokesperson said: "Passengers can be reassured that they will travel as normal. This is an important time for the country, and we will not let these unnecessary strikes disrupt journeys.
"We have activated our contingency plans and deployed 750 additional colleagues and the entire management team who will be on-hand in the terminals providing assistance to passengers."
