The budget carrier saw a 23% rise in revenue to €2.2bn for the year to 30 September.
The number of passengers flying with Ryanair rose by 10% to 40.1 million people for the full year.
The airline's average fare increased over the summer by 12% to €44 due to a 12% growth in its reach of routes and destinations across Europe.
Michael O’Leary, chief executive of Ryanair, said: "A 17% increase in half-year net profit to €452m is testimony to the robustness of Ryanair's lowest cost/lowest fare model which continues to deliver traffic and profit growth even during a deep recession.
"We continue to gain market share across Europe from the big three high-fare flag carrier groups led by Air France, BA and Lufthansa. We expect this trend to continue as consumers switch to Ryanair for the lowest fares, the most on-time flights, and the best customer service."
Ryanair has continued to invest in its marketing throughout the year, regularly advertising seat sales in the national newspapers of the destinations it flies to.
The weekly promotional campaign from the airline sees up to a million passenger seats being sold for three, four or five euros, including tax.
Ryanair said that it does not have plans to increase its market spend at this time.
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