Deal alert: Fly to Martha's Vineyard or Nantucket for less than $80 round-trip

If you're planning a trip to Martha's Vineyard or Nantucket, Massachusetts, JetBlue is making the flight there much cheaper with a limited-time fare deal.

As first reported by Scott's Cheap Flights Premium, JetBlue is offering round-trip flights from cities such as Boston and New York to both Martha's Vineyard (MVY) and Nantucket (ACK) for less than $80 on various dates in September and October.

This is an impressive discount from the usual fares, which can easily be more than $300 round-trip from the Northeast, based on a TPG search on Google Flights.

But act fast: This fare deal ends tomorrow night.

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The days of the week on which the highly discounted fares are offered vary for each route, but the cheap fares are generally found between Sept. 1 and Oct. 11.

An example search for flights between Boston (BOS) and MVY indicates that the cheapest flights for this route are generally found on Mondays, Tuesdays, Wednesdays and Saturdays in all of September and some of October.

Available on Blue Basic fares, this fare deal is great for those who don't have much luggage. A fare in Blue -- JetBlue's normal economy fare -- would cost $100 extra and would include free seat selection, a carry-on bag and no change fees. However, a round-trip flight for $179 is still much cheaper than the average ticket to MVY or ACK.

Related: How points and miles saved me over $2,000 on a trip to Nantucket and Cape Cod

Below is a list of all of the cheap fares to MVY and ACK as part of JetBlue's limited-time fare deal. All fares are Blue Basic fares and expire tomorrow night.

The complete list of nonstop flight deals to MVY and ACK

Round-trip to Martha's Vineyard (MVY) from:

• Boston (BOS): $79.
• New York (JFK): $79.
• New York (LGA): $79.
• Newark (EWR): $79.
• Washington, D.C. (DCA): $99.

Round-trip to Nantucket (ACK) from:

• Boston (BOS): $99.
• New York (JFK): $99.
• New York (LGA): $77.
• White Plains/Westchester County Airport (HPN): $97.

Flight savings opportunities from other parts of the country

While the best deals are found on nonstop flights from the various Northeast airports listed above, cheap one-stop flights to MVY and ACK can be found from other parts of the country, too, as part of the same JetBlue fare deal.

For example, JetBlue flights from Orlando (MCO) to MVY with one stop in LGA start at $204 round-trip in Blue Basic. So, those from outside the Northeast Corridor can capitalize on the cheap flights to MVY or ACK, too.

And almost every city that JetBlue serves has discounted fares as part of the same limited-time fare deal that ends tomorrow, so if you book soon, you could see impressive discounts for flights throughout JetBlue's network.

Make the most out of your flight purchase

Be sure to use the right card to make the most out of your airfare purchases, such as The Platinum Card® from American Express (5x on flights booked directly with airlines or American Express Travel), Chase Sapphire Reserve (3x on travel), American Express® Gold Card (3x on flights booked directly with airlines or American Express Travel), Citi Premier® Card (3x on air travel), Citi Prestige® Card (5x on air travel) or the Chase Sapphire Preferred Card (2x on travel). Read this guide to learn more about the best credit cards to use when purchasing flights.

The information for the Citi Prestige Card has been collected independently by The Points Guy. The card details on this page have not been reviewed or provided by the card issuer.