TAP deal: Book flights to Europe starting at $345

If booking that trip to Europe over the summer is too expensive, opt for a fall or winter flight instead. TAP Air Portugal is offering round-trip flights to Europe starting at $345.

With these TAP deals, you can fly from Boston, Miami and Washington, D.C., to Barcelona, Dublin, Paris, Zurich and Madrid. Of the three U.S. cities, Washington has the most availability, with flights to Dublin, Paris and Zurich.

The travel dates for these deals are from October to December, with availability during Thanksgiving. Flights during Christmas and New Year's Eve are excluded from this deal.

These fares are a steal, so be sure to plan your trip to Europe quickly, as these low prices are only expected to last for the next two to three days.

Deal basics

Airline: TAP Air Portugal.
Routes: From Boston, Miami and Washington to Europe.
How to book: Use Google Flights to determine your best dates and then book directly with the airline of your choice.
Travel dates: October to December; includes Thanksgiving, but excludes Christmas and New Year's Eve.
Book by: The next two to three days.

Kudos to Going for flagging these deals. At $49 a year, the site's Premium membership offers discounts of up to 90% and features a 14-day free trial. The Elite membership also sources premium economy, business-class and first-class deals.

Sample flights

TAP is only offering these marked-down flights in three cities. However, they are all solid deals if you're trying to visit Europe this year but don't want to deal with the high fares typically associated with spring and summer travel. Plus, with the fall and winter travel dates, you'll most likely avoid the large crowds of tourists.

Here are all the flights TAP is offering. Keep in mind that all flights have a layover in Lisbon, Portugal:

• Boston Logan International Airport (BOS) to Josep Tarradellas Barcelona-El Prat Airport (BCN), starting at $345.
• Dulles International Airport (IAD) to Dublin Airport (DUB), starting at $375.
• IAD to Paris-Orly Airport (ORY), starting at $394.
• IAD to Zurich Airport (ZRH), starting at $404.
• Miami International Airport (MIA) to Adolfo Suárez Madrid-Barajas Airport (MAD), starting at $408.

We recommend searching through Google Flights to determine your best dates and then booking your flights on the airline's website. Direct airline bookings are more reliable if a flight is delayed, canceled or experiences a booking change.

If you plan on flying from Boston to visit Barcelona in November, Google Flights shows the TAP flight as the option with the lowest airfare.

TAP only offers one returning flight that would keep the fare the same. It departs from Barcelona at 2:35 p.m.

While Google Flights will show that the price is $332 round-trip when looking for flights, remember that the $332 price tag isn't necessarily true. If you were to book the flight directly on TAP's website, it would cost $345.

Sometimes there are price discrepancies between Google Flights and the airline's website because Google Flights features third-party booking sites, which typically promise lower fares.

These deals are also for the basic economy class. TAP's basic economy fare, known as "Discount" on the website, only lets passengers bring a carry-on and a personal item. Passengers can also receive a meal on board.

Seat selection prices range from $13 to $115 — the more expensive seats include more legroom and are closer to the front of the aircraft. The more expensive seats also include USB outlets.

You also have the option to check baggage, which costs $85 one-way.

Maximize your purchase

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Bottom line

Despite availability limited to only Boston, Miami and Washington, these TAP fares are incredibly low and still worth snatching up before they sell out. Basic economy round-trip fares can typically cost at least $500, and all of these TAP fares are within the $300-to-low-$400 range.

Fares can change quite frequently — especially as seats fill up — so be sure to book these flights as soon as possible.