What is the cheapest airline to fly from Islip, New York to San Antonio round-trip?

Currently priced at $331, Southwest will fly you from Islip, New York to San Antonio and back. In addition to Southwest, many other airlines offer competitively priced options for your trip.

What is the cheapest day to fly from Islip, New York to San Antonio?

Travelers seeking maximum savings on their Islip, New York to San Antonio flight should consider departing on Tuesday mornings when fares are most often at their lowest. Tuesday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

In terms of precipitation, rainfall in San Antonio ranges from 1.6 - 3.7 inches per month. May is typically the wettest month, when rainfall can reach 3.7 in. December is typically the driest time to visit San Antonio when rainfall is around 1.6 in.

If weather is an important factor for your trip to San Antonio, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 84.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 51.8 F).

How far in advance should I book a flight from Islip, New York to San Antonio?

Travelers have found it’s best to book a flight 34 days in advance to save up to 82% compared to booking the same week of travel. As your travel date approaches, the cost of this flight route may potentially increase. While opting to book 34 days out may not be an option for all, there are still additional ways to secure a deal in the near future. You might find a flight from Islip, New York to San Antonio 1-2 weeks in advance for as low as $398, or $555 for flights within the next 24 hours.

What is the cheapest month to fly from Islip, New York to San Antonio?

September is one of the best times of the year to fly to San Antonio from Islip, New York. Prices for September average $376 per person but you can even find prices for as low as $97. The most expensive prices can be found in the month of December. Opting for a September flight can save you 33% on your journey compared to booking in December

What is the cheapest time of day to fly from ISP to SAT?

A simple way to save on the total cost of your ticket is to fly from Islip, New York to San Antonio at noon. If you’re flexible enough to do this you can expect to save up to 3% on your trip compared to booking a flight in the morning.

Can I find deals for flights from Islip to San Antonio that include hotel bookings?

Yes. In addition to deals on Islip to San Antonio flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Islip to San Antonio?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Islip to San Antonio.

Can I find deals for business class flights from Islip to San Antonio?

Yes. Cheapflights offers flight deals from Islip to San Antonio by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$112+ Flights from Islip, NY to San Antonio

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Cheap flight deals from Islip to San Antonio

Round-trip from	$331 (Southwest)
One-way from	$112 (Kiwi.com)
Popular in	December
Cheapest in	September
Average price	$278

From Islip Long Island to San Antonio

Search Deals

One-way flight from Islip Long Island to San Antonio

Search Deals

Highest demand for flights based on searches. 11% potential increase in price ($50 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 3% potential price decrease ($11 potential savings vs. average RT price).

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Average for round-trip flights in August 2025

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Find flight deals from Islip to San Antonio

Cheapest flights from Islip to San Antonio
Explore the most affordable flight options available from Islip to San Antonio. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Tue 9/3012:30 pmISP - SAT

1 stop8h 40mSouthwest

Fri 10/34:35 pmSAT - ISP

1 stop6h 10mSouthwest

Deal found 8/11

$331

Sat 9/1312:15 pmISP - SAT

2 stops8h 05mSouthwest

Wed 9/175:35 amSAT - ISP

1 stop8h 35mSouthwest

Deal found 8/11

$336

Tue 11/185:40 amISP - SAT

1 stop8h 25mSouthwest

Sat 11/225:30 pmSAT - ISP

1 stop5h 25mSouthwest

Deal found 8/12

$355

Sun 9/1411:25 amISP - SAT

1 stop25h 15mMultiple Airlines

Wed 9/179:47 pmSAT - ISP

2 stops35h 53mMultiple Airlines

Deal found 8/11

$368

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Sat 8/233:34 pmSAT - ISP

2 stops19h 35mFrontier

Deal found 8/11

$395

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Fri 8/228:18 pmSAT - ISP

2 stops16h 41mFrontier

Deal found 8/11

$411

Mon 9/86:00 amISP - SAT

1 stop5h 55mSouthwest

Mon 9/155:10 amSAT - ISP

1 stop5h 50mSouthwest

Deal found 8/11

$412

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Sun 8/248:18 pmSAT - ISP

2 stops14h 58mFrontier

Deal found 8/12

$416

Best flights from Islip to San Antonio
Discover carefully curated flight deals from Islip to San Antonio that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 13, 2025.

Tue 9/3012:30 pmISP - SAT

1 stop8h 40mSouthwest

Fri 10/34:35 pmSAT - ISP

1 stop6h 10mSouthwest

Deal found 8/11

$331

Sun 9/1411:25 amISP - SAT

1 stop25h 15mMultiple Airlines

Wed 9/179:47 pmSAT - ISP

2 stops35h 53mMultiple Airlines

Deal found 8/11

$368

Sat 9/1312:15 pmISP - SAT

2 stops8h 05mSouthwest

Wed 9/175:35 amSAT - ISP

1 stop8h 35mSouthwest

Deal found 8/11

$336

Tue 11/185:40 amISP - SAT

1 stop8h 25mSouthwest

Sat 11/225:30 pmSAT - ISP

1 stop5h 25mSouthwest

Deal found 8/12

$355

Mon 9/86:00 amISP - SAT

1 stop5h 55mSouthwest

Mon 9/155:10 amSAT - ISP

1 stop5h 50mSouthwest

Deal found 8/11

$412

Last-minute flights from Islip to San Antonio
Discover last-minute flight deals from Islip to San Antonio. Data last updated August 13, 2025 and is based on user searches.

Mon 8/183:05 pmISP - SAT

2 stops8h 20mSouthwest

Fri 8/227:40 amSAT - ISP

2 stops7h 50mSouthwest

Deal found 8/11

$857

Mon 8/184:33 pmISP - SAT

3 stops20h 28mMultiple Airlines

Fri 8/2211:38 amSAT - ISP

2 stops22h 20mMultiple Airlines

Deal found 8/11

$1,296

Tue 8/196:05 amISP - SAT

1 stop9h 00mSouthwest

Tue 8/265:35 amSAT - ISP

1 stop5h 20mSouthwest

Deal found 8/12

$692

Tue 8/1911:53 amISP - SAT

2 stops25h 08mMultiple Airlines

Tue 8/268:55 amSAT - ISP

3 stops25h 03mMultiple Airlines

Deal found 8/12

$1,177

Wed 8/208:00 amISP - SAT

2 stops36h 33mFrontier

Mon 8/255:27 pmSAT - ISP

2 stops29h 32mFrontier

Deal found 8/11

$471

Wed 8/206:05 amISP - SAT

2 stops9h 50mSouthwest

Mon 8/255:10 amSAT - ISP

1 stop5h 50mSouthwest

Deal found 8/11

$719

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Sat 8/233:34 pmSAT - ISP

2 stops19h 35mFrontier

Deal found 8/11

$395

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Fri 8/228:18 pmSAT - ISP

2 stops16h 41mFrontier

Deal found 8/11

$411

Thu 8/217:33 pmISP - SAT

2 stops22h 09mFrontier

Sun 8/248:18 pmSAT - ISP

2 stops14h 58mFrontier

Deal found 8/12

$416

Thu 8/213:05 pmISP - SAT

1 stop8h 00mSouthwest

Sat 8/235:05 amSAT - ISP

1 stop6h 00mSouthwest

Deal found 8/11

$847

Thu 8/213:05 pmISP - SAT

2 stops8h 05mSouthwest

Fri 8/223:30 pmSAT - ISP

1 stop6h 25mSouthwest

Deal found 8/11

$852

Thu 8/286:05 amISP - SAT

1 stop10h 40mMultiple Airlines

Mon 9/15:53 pmSAT - ISP

2 stops29h 06mMultiple Airlines

Deal found 8/12

$423

One-way flights from Islip to San Antonio
Search for one-way flight options from Islip to San Antonio. Find affordable one-way fares based on user searches. Data last updated August 13, 2025.

Sun 9/1411:25 amISP - SAT

1 stop25h 15mMultiple Airlines

Deal found 8/11

$112

Sat 9/135:05 pmISP - SAT

1 stop21h 44mMultiple Airlines

Deal found 8/11

$166

Sat 9/1312:15 pmISP - SAT

2 stops9h 55mSouthwest

Deal found 8/11

$168

Fri 10/35:30 amISP - SAT

1 stop6h 20mSouthwest

Deal found 8/13

$169

Fri 10/35:05 pmISP - SAT

3 stops27h 27mMultiple Airlines

Deal found 8/13

$176

Fri 10/318:48 pmISP - SAT

2 stops19h 26mFrontier

Deal found 8/13

$201

Fly from

Fly to

Route

Depart

Return

Price

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Tue 9/30

12:30 pm-8:10 pm

1 stop8h 40m

San Antonio

Fri 10/3

4:35 pm-11:45 pm

1 stop6h 10m

$331

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Sat 9/13

12:15 pm-7:20 pm

2 stops8h 05m

San Antonio

Wed 9/17

5:35 am-3:10 pm

1 stop8h 35m

$336

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Tue 11/18

5:40 am-1:05 pm

1 stop8h 25m

San Antonio

Sat 11/22

5:30 pm-11:55 pm

1 stop5h 25m

$355

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Sun 9/14

11:25 am-11:40 am

1 stop25h 15m

San Antonio

Wed 9/17

9:47 pm-10:40 am

2 stops35h 53m

$368

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Mon 9/8

6:00 am-10:55 am

1 stop5h 55m

San Antonio

Mon 9/15

5:10 am-12:00 pm

1 stop5h 50m

$412

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Sun 9/14

11:25 am-11:40 am

1 stop25h 15m

$112

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Fri 10/3

5:05 pm-2:27 pm

2 stops22h 22m

$166

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Sat 9/13

5:05 pm-1:49 pm

1 stop21h 44m

$166

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Sat 9/13

12:15 pm-9:10 pm

2 stops9h 55m

$168

IslipSan Antonio

ISP - SAT

ISPSAT

Islip Long Island

Fri 10/3

5:30 am-10:50 am

1 stop6h 20m

$169

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/11

Showing 1-10 of 12 results

Best time to book a flight from Islip to San Antonio

Have a flexible travel schedule? Discover the best time to fly to San Antonio from Islip with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Islip to San Antonio

What is the cheapest month to book a flight from Islip, New York to San Antonio?

Currently, August is the cheapest month in which you can book a flight from Islip, New York to San Antonio (average of $295). Flying from Islip, New York to San Antonio in March is currently the most expensive (average of $376). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Reviews of airlines servicing San Antonio

Read through reviews of airlines operating flights from Islip to San Antonio, such as Southwest. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Southwest

8.0

Very good

4,246 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Southwest

8.0

Very good

4,246 reviews

Southwest

8.0

Very good

4,246 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Related info for your journey

What is the cheapest airline to fly from Islip, New York to San Antonio round-trip?
Currently priced at $331, Southwest will fly you from Islip, New York to San Antonio and back. In addition to Southwest, many other airlines offer competitively priced options for your trip.
Can I find deals for flights from Islip to San Antonio that include hotel bookings?
Yes. In addition to deals on Islip to San Antonio flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Islip to San Antonio?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Islip to San Antonio.
Can I find deals for business class flights from Islip to San Antonio?
Yes. Cheapflights offers flight deals from Islip to San Antonio by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Islip, New York to San Antonio?
Currently, August is the cheapest month in which you can book a flight from Islip, New York to San Antonio (average of $295). Flying from Islip, New York to San Antonio in March is currently the most expensive (average of $376). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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Top airline flying from Islip to San Antonio

Airline	Cheapest	Average	Flexibility	On-time
Southwest	Cheapest$375	Average$462	FlexibilityNo cancel fee	On-time63%

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$112+ Cheap flights from Islip, NY to San Antonio (ISP - SAT)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/14. Fares are subject to change and may not be available on all flights or dates of travel.

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Cheap flight deals from Islip to San Antonio

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Find flight deals from Islip to San Antonio

Cheapest flights from Islip to San AntonioExplore the most affordable flight options available from Islip to San Antonio. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Explore the most affordable flight options available from Islip to San Antonio. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Islip to San Antonio that are best for you.

Best time to book a flight from Islip to San Antonio

Have a flexible travel schedule? Discover the best time to fly to San Antonio from Islip with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Islip to San Antonio

What is the cheapest month to book a flight from Islip, New York to San Antonio?

Reviews of airlines servicing San Antonio

Read through reviews of airlines operating flights from Islip to San Antonio, such as Southwest. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Islip to San Antonio. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What is the cheapest airline to fly from Islip, New York to San Antonio round-trip?

Can I find deals for flights from Islip to San Antonio that include hotel bookings?

How can I find direct flights from Islip to San Antonio?

Can I find deals for business class flights from Islip to San Antonio?

What is the cheapest month to book a flight from Islip, New York to San Antonio?

Traveling to a place near San Antonio?

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Islip to San Antonio

See prices for flight routes from nearby airports that may be better suited for you.

Top airline flying from Islip to San Antonio

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Cheapest flights from Islip to San Antonio
Explore the most affordable flight options available from Islip to San Antonio. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.