Question : If your plans are flexible, have you considered changing your departure day?
Answer : The cheapest day to fly in May is Thursday. Being flexible with your travel days garners even more savings during booking.
Question : How long do most people visit Athens?
Answer : Of course you're not most people, but if you were, you'd stay roughly seven days.
Question : Which airline is offering the cheapest flight from OPO to ATH?
Answer : Aegean Airlines is your best bet for finding that coveted low fare. They're offering fares as low as $245, while prices for other flights are as high as $517.
Question : How much should a trip from Porto (OPO) to Athens (ATH) cost?
Answer : Flight prices change more than the majority of routes from Portugal for OPO to ATH. They range from $245 to $517. The further out you book a route, the more likely you are to save.
Question : In the next four weeks, what day should you book your trip?
Answer : Since low prices are preferred, look at May 4th. As of Apr 24th, it's showing the cheapest ticket sales at $245. That is 27% below the average price for this route, so you can spend that extra money on an adventure rather than the flight.