Cheap flights from Ontario to San Juan from $268 ONT → SJU
Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU)
The cheapest return found recently is $447 with United Airlines, 7 Dec – 13 Dec, found 2 days ago. The cheapest one-way found recently is $268 with Southwest Airlines, 25 Mar 2027, found 3 days ago.
- Cheapest one-way found recently
- $268, found 3 days ago
- Cheapest return found recently
- $447, 7 Dec to 13 Dec
- Usual return price
- $447 to $460
- Cheapest month to fly
- December 2026, return fares from $441 found in the last 7 days
Return
The cheapest return fare on each of 5 departure dates is usually $447 to $460.
Cheapest return found recently
$447
7 Dec – 13 Dec · United Airlines
Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU)
Leaves 5:00 a.m. · Return leaves 5:01 a.m. · 19 h 56 min of travel, both ways together
out 1 stop, back 1 stop · via Denver International Airport (DEN), Hartsfield-Jackson Atlanta International Airport (ATL) · separate tickets likely: collect your bags and check in again
found 2 days ago
Cheapest nonstop return
None seen yet.
Found recently, and the cheapest we hold
$447 7 Dec – 13 Decfound 2 days agoSee prices for these dates
$441 7 Dec – 13 Decfound 7 days agoSee prices for these dates
What have prices looked like?
Over 49 days, 24 Sept to 11 Nov, the cheapest return we saw each day was $350 to $748.
Those were the prices on those days, not today's.
Is this a good return price?
Compared with the cheapest return fare on each of 5 departure dates from 6 Dec to 25 Mar 2027, found by travelers' searches in the last 7 days (economy, the price the seller showed on Aviasales). The usual range is the middle half of those prices.
Could nearby dates be cheaper?
No. We hold 6-night return fares on 2 other departure dates within 3 days of 7 Dec, and none is cheaper.
Every date we hold
33 fares on 5 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 6 Dec – 12 Dec | $450 | United Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | out 1 stop, back 1 stop | found 7 days ago | See prices for these dates |
| 7 Dec – 13 Dec | $441 | American Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | out 1 stop, back 1 stop | found 7 days ago | See prices for these dates |
| 8 Dec – 13 Dec | $447 | United Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | out 1 stop, back 1 stop | found 2 days ago | See prices for these dates |
| 8 Feb 2027 – 13 Feb 2027 | $615 | American Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | out 1 stop, back 1 stop | found 4 days ago | See prices for these dates |
| 25 Mar 2027 – 5 Apr 2027 | $460 | Southwest Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | out 2 stops, back 2 stops | found 3 days ago | See prices for these dates |
Which month looks cheapest?
December 2026 is the cheapest month — from $441.
Airlines on the cheapest dates: United Airlines, American Airlines, Southwest Airlines.
One-way
Not enough comparable prices yet for a usual one-way price.
Cheapest one-way found recently
$268
25 Mar 2027 · Southwest Airlines
Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU)
Leaves 5:15 a.m. · 14 h 40 min trip
2 stops
found 3 days ago
Cheapest nonstop one-way
None seen yet.
Found recently, and the cheapest we hold
$268 25 Mar 2027found 3 days agoOpen this trip
It is also the cheapest one-way we hold, of any age.
What have prices looked like?
Over 18 days, 9 Oct to 11 Nov, the cheapest one-way we saw each day was $247 to $324.
18 days is a short history, so treat this range as an early guide.
Those were the prices on those days, not today's.
Is this a good one-way price?
Not enough comparable prices yet: we hold one-way fares on 1 departure date and need at least 3 to say what is usual.
Could nearby dates be cheaper?
We hold no other one-way fares leaving within 3 days of 25 Mar 2027 to compare.
Every date we hold
1 fares on 1 departure dates
See every date as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 25 Mar 2027 | $268 | Southwest Airlines | Ontario International Airport (ONT) → Luis Munoz Marin International Airport (SJU) | 2 stops | found 3 days ago | Open this trip |
Airlines on the cheapest dates: Southwest Airlines.
Premium cabin fares from Ontario to San Juan
We hold no premium economy, business or first-class fares for this route: we collect them for the busiest routes, and this one is not among them yet.
Today's prices for 7 Dec – 13 Dec in another cabin: Premium economy · Business · First
Today's prices for 25 Mar 2027 in another cabin: Premium economy · Business · First
How far ahead were prices cheapest for Ontario to San Juan?
Return
Fares 30 to 59 days before departure were typically 20% lower than 0 to 6 days before departure.
From the cheapest return each day between 24 Sept and 11 Nov (49 days), grouped by how many days ahead the flight left; one adult in economy.
Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.
Prices reflect recent searches — current fares may differ.
See these ranges as a table
| Booked ahead by | Typical fare | Cheapest day | Above the cheapest | Days of prices |
|---|---|---|---|---|
| 0–6 days | $531 | $488 | +25% | 9 |
| 14–29 days | $450 | $439 | +6% | 9 |
| 30–59 days | $426 | $377 | Cheapest seen | 39 |
| 60–89 days | $549 | $453 | +29% | 27 |
| 90–179 days | $495 | $350 | +16% | 29 |
| 180+ days | $547 | $547 | +28% | 8 |
One-way
Not enough history yet: in 18 days of one-way prices, 9 Oct to 11 Nov, fewer than 3 booking ranges had prices on 7 days or more.
Could a nearby airport be cheaper?
A different airport at either end can change the fare — sometimes a lot.
Return
Los Angeles → San Juan
56 km from Ontario
$265
$182 less than flying from Ontario
7 Dec – 13 Dec · LAX → SJU · out 1 stop, back 1 stop
found 2 days ago
Long Beach → San Juan
60 km from Ontario
$607
$160 more than flying from Ontario
25 Mar 2027 – 5 Apr 2027 · LGB → SJU · out 2 stops, back 2 stops
found 3 days ago
Cheapest recent price on each route — round trip, per traveler in Economy. Distances are in a straight line.
One-way
Los Angeles → San Juan
56 km from Ontario
$232
$36 less than flying from Ontario
25 Mar 2027 · LAX → SJU · 2 stops
found 3 days ago
Cheapest recent price on each route — one way, per traveler in Economy. Distances are in a straight line.
Live price for these dates
The cheapest return found recently is for 7 Dec – 13 Dec. A live search on this page shows what those dates cost now, for one adult in economy.
Questions about this trip
How much is a return flight from Ontario to San Juan?
The cheapest return found recently is $447 with United Airlines, 7 Dec to 13 Dec, found 2 days ago. The cheapest return we hold, of any age, is $441 with American Airlines, 7 Dec to 13 Dec, found 7 days ago. The cheapest return fare on each of 5 departure dates is usually $447 to $460.
How much is a one-way flight from Ontario to San Juan?
The cheapest one-way found recently is $268 with Southwest Airlines, 25 Mar 2027, found 3 days ago.
What is the cheapest month to fly from Ontario to San Juan?
December 2026 is the cheapest month for a return, from $441, 7 Dec to 13 Dec, found 7 days ago.
How far ahead should I book a flight from Ontario to San Juan?
In 49 days of prices between 24 Sept and 11 Nov, return fares 30 to 59 days before departure were typically 20% lower than 0 to 6 days before departure.
How long is the flight from Ontario to San Juan?
The cheapest one-way found recently, with Southwest Airlines on 25 Mar 2027, takes 14 h 40 min with 2 stops.
Which airlines have the cheapest flights from Ontario to San Juan?
Between 6 Dec and 25 Mar 2027, United Airlines has the cheapest return on 2 of the 5 departure dates we hold, American Airlines on 2 and Southwest Airlines on 1.
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