Johan Lundgren, CEO of the airline, said the increase in capacity will start over the next two months.
He said: “I am really encouraged that we have seen higher than expected levels of demand with a load factor of 84 per cent in July with destinations like Faro and Nice remaining popular with customers.
“Our bookings for the remainder of the summer are performing better than expected and as a result we have decided to expand our schedule over the fourth quarter [July to September] to fly 40 per cent of capacity. This increased flying will allow us to connect even more customers to family or friends and to take the breaks they have worked hard for.”
The airline had previously only expected to operate at 30 per cent of its normal capacity.
Lundgren made the comments as part of the company's latest trading update, released on 4 August.
Easyjet grounded its entire fleet on 30 March due to the global impact of coronavirus.
The airline resumed its services on 15 June, initially with just 10 aircraft focusing on domestic routes. There were also a handful of flights to France and Italy.
Due to demand and the relaxation of government restrictions, this was increased to 147 in July according to the trading update. In August, this will peak to around 210.
Despite the uplift in demand, the company still made a loss of £324.5m before tax.
The airline is currently going through a restructuring process and is looking to reduce its staff by 30 per cent.