The new leasing deals mean the airline, which began flights to Stansted in June, will have 10 Airbus A320 and A321 aircraft by spring 2023.
Play has taken advantage of favourable leasing arrangements caused by the pandemic and has secured new aircraft direct from Airbus via lessors.
Play will have a fleet of six by spring 2022, when it hopes to begin offering connecting flights between the UK and US.
In August, the airline saw load factors of 46%, an increase on its first month of operation, when the average was 41.7%.