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Philadelphia to San Juan flights in December 2026 from $305 PHL, TTN → SJU

Philadelphia International Airport (PHL), Trenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)

For departures in December 2026, the cheapest return found recently is $305 with Frontier Airlines, 21 Dec – 16 Jan 2027, found 3 days ago. The cheapest one-way found recently is $362 with Frontier Airlines, 3 Dec, found 7 days ago.

Return

In December 2026, the cheapest return fare on each of 9 departure dates is usually $239 to $969. Across all 16 departure dates we hold on this route, it is usually $211 to $569.

Cheapest return found recently

$305

21 Dec – 16 Jan 2027 · Frontier Airlines

Philadelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)

out nonstop, back nonstop

found 3 days ago

See prices for these datesCheck today's price

Cheapest we hold, of any age

$147

8 Dec – 12 Dec · Frontier Airlines

Philadelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)

out 1 stop, back nonstop

found 6 days ago

See prices for these datesCheck today's price

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The cheapest dates in December 2026

DatesFromAirlineStopsFound
8 Dec – 12 Dec$147Frontier Airlinesout 1 stop, back nonstopfound 6 days agoSee prices for these dates
30 Dec – 2 Feb 2027$173Frontier Airlinesout 1 stop, back nonstopfound 4 days agoSee prices for these dates
3 Dec – 7 Dec$239Frontier Airlinesout nonstop, back 1 stopfound 4 days agoSee prices for these dates
21 Dec – 16 Jan 2027$305Frontier Airlinesout nonstop, back nonstopfound 3 days agoSee prices for these dates
25 Dec – 27 Dec$530Frontier Airlinesout 1 stop, back 1 stopfound 4 days agoSee prices for these dates

Every date we hold

9 departure dates

3 Dec – 7 Dec: $239, found 4 days ago8 Dec – 12 Dec: $147, found 6 days ago21 Dec – 16 Jan 2027: $305, found 3 days ago23 Dec – 3 Jan 2027: $969, found 3 days ago24 Dec – 3 Jan 2027: $687, found 3 days ago25 Dec – 27 Dec: $530, found 4 days ago26 Dec – 2 Jan 2027: $1,009, found 5 days ago27 Dec – 3 Jan 2027: $1,341, found 5 days ago30 Dec – 2 Feb 2027: $173, found 4 days agoDec
See the chart as a table
The cheapest price seen for each departure date — per traveler in Economy.
DatesFromAirlineAirportsStopsFound
3 Dec – 7 Dec$239Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out nonstop, back 1 stopfound 4 days agoSee prices for these dates
8 Dec – 12 Dec$147Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out 1 stop, back nonstopfound 6 days agoSee prices for these dates
21 Dec – 16 Jan 2027$305Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out nonstop, back nonstopfound 3 days agoSee prices for these dates
23 Dec – 3 Jan 2027$969Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)out 1 stop, back 1 stopfound 3 days agoSee prices for these dates
24 Dec – 3 Jan 2027$687Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out 1 stop, back 2 stopsfound 3 days agoSee prices for these dates
25 Dec – 27 Dec$530Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out 1 stop, back 1 stopfound 4 days agoSee prices for these dates
26 Dec – 2 Jan 2027$1,009Frontier AirlinesPhiladelphia International Airport (PHL) → Luis Munoz Marin International Airport (SJU)out 1 stop, back 1 stopfound 5 days agoSee prices for these dates
27 Dec – 3 Jan 2027$1,341Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)out 1 stop, back 1 stopfound 5 days agoSee prices for these dates
30 Dec – 2 Feb 2027$173Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)out 1 stop, back nonstopfound 4 days agoSee prices for these dates

Which month looks cheapest?

December 2026 is the cheapest month — from $147.

November 2026From $2242 departure dates13 Nov – 16 Nov · found 4 days agoSee prices for these dates
December 2026From $147Cheapest seen9 departure dates8 Dec – 12 Dec · found 6 days agoSee prices for these dates
January 2027From $1471 departure date8 Jan 2027 – 7 Feb 2027 · found 4 days agoSee prices for these dates
February 2027From $1622 departure dates8 Feb 2027 – 14 Feb 2027 · found 2 days agoSee prices for these dates
April 2027From $3661 departure date28 Apr 2027 – 1 May 2027 · found 2 days agoSee prices for these dates
May 2027From $3831 departure date7 May 2027 – 22 May 2027 · found 4 days agoSee prices for these dates

One-way

In December 2026, the cheapest one-way fare on each of 3 departure dates is usually $366 to $483. Across all 10 departure dates we hold on this route, it is usually $97 to $313.

Cheapest one-way found recently

$362

3 Dec · Frontier Airlines

Trenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)

1 stop

found 7 days ago

Open this tripCheck today's price

It is also the cheapest one-way we hold, of any age.

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The cheapest dates in December 2026

DatesFromAirlineStopsFound
3 Dec$362Frontier Airlines1 stopfound 7 days agoOpen this trip
28 Dec$370Frontier Airlines1 stopfound 7 days agoOpen this trip
23 Dec$595Frontier Airlines1 stopfound 7 days agoOpen this trip

Every date we hold

3 departure dates

3 Dec: $362, found 7 days ago23 Dec: $595, found 7 days ago28 Dec: $370, found 7 days agoDec
See the chart as a table
The cheapest price seen for each departure date — per traveler in Economy.
DatesFromAirlineAirportsStopsFound
3 Dec$362Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)1 stopfound 7 days agoOpen this trip
23 Dec$595Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)1 stopfound 7 days agoOpen this trip
28 Dec$370Frontier AirlinesTrenton-Mercer Airport (TTN) → Luis Munoz Marin International Airport (SJU)1 stopfound 7 days agoOpen this trip

Which month looks cheapest?

November 2026 is the cheapest month — from $46.

November 2026From $46Cheapest seen2 departure dates17 Nov · found 4 days agoOpen this trip
December 2026From $3623 departure dates3 Dec · found 7 days agoOpen this trip
January 2027From $831 departure date17 Jan 2027 · found 7 days agoOpen this trip
February 2027From $1671 departure date14 Feb 2027 · found 3 days agoOpen this trip
April 2027From $1432 departure dates28 Apr 2027 · found 2 days agoOpen this trip
May 2027From $1371 departure date1 May 2027 · found 4 days agoOpen this trip

Prices are what travelers' searches on Aviasales found in the last 7 days, in US dollars: the price the seller showed on Aviasales; bags may cost extra. Fares change, so check today's price before you book. How our prices work