Route brief · BOS → SJU
Boston → San Juan
$200
−48% vs typical
seasonal median $385 · difference $185
Sep 24 – Sep 27 · 3 nights
Frontier Airlines1 stop
- Usual monthly lows
- $290–$446
- Board rank
- Stronger than 95%
- Route sample
- 5 observed months
Cached fare — the booking search re-prices live before you pay.
Destination briefSJUSan JuanFive centuries of old town on a Caribbean island that takes US dollars and needs no passport from the States.Best windowDec–AprAirportsLuis Muñoz Marín (SJU)All routes into San JuanWhen this route gets cheap.
Cached-fare history: across 5 months, Sep is the cheapest for BOS → SJU. Best time to be there: Dec–Apr.
Fares bottom out in September around $200 and peak in December near $463 — a $263 spread across the 5 months we track. The cheapest itinerary we are tracking makes one stop and takes about 6.5 hours outbound, on a 3-night trip — ticketed under Frontier Airlines, which on a connecting fare need not operate every leg. At $200 for 2,698 km each way, that works out to about $37 per 1,000 km flown. That is below the $39 typical of medium-haul fares here. Across the 6 departure cities we track at a similar distance from San Juan, this fare ranks 3rd — 37% above the $146 from New York. It is also the cheapest of the 7 routes of similar length we watch out of Boston.
The 6 days we hold a cached fare for
Tap a date → live search
The median cached fare across this calendar is 23% higher than when tracking began on Aug 8 — $292 then versus $358 now, across 5 recorded snapshots. This is a calendar-level trend, so an individual deal above can be lower. The lowest single day we have seen here is $200, on Sep 24.
These are the only days we have a cached price for on this route so far — not the only days it flies. The search above covers any date.
Cheapest in Sep · around $200
48% below the $385 typical fare
Cheapest round-trip fare found per month · Boston → San Juan · cached-price history
Route facts
- Airports
- Logan (BOS) ↔ Luis Muñoz Marín (SJU)
- Flight time
- ~6.5 hours outbound
- Distance
- ~2,698 km each way
- Typical price
- $385 round-trip (seasonal median)
- Airlines on the board
- Frontier Airlines
- Itineraries
- Connections on current fares
- Best months to visit
- Dec–Apr
BOS → SJU, answered.
Is $200 a good price for Boston to San Juan?
Yes — the seasonal median for this route is around $385 round-trip. At $200 you're 48% below that, saving about $185, which we rate rare for this route.
What is the cheapest month to fly from Boston to San Juan?
Across 5 months of cached-fare history, Sep comes out cheapest on this route. The best months to actually be in San Juan are Dec–Apr — when those overlap, that's your window.
How far in advance should I book BOS → San Juan?
We do not publish a number for this, because we cannot measure it yet. Answering it honestly means watching the same departure date on this route over many weeks as it approaches, and that archive is still filling up — so any "book N days ahead" figure here would be borrowed from somewhere else rather than measured. What we can measure is which month is cheap: across 5 months of cached fares, Sep comes out lowest on this route. See /guides/what-moves-a-flight-price/ for what does move a fare.
Are there nonstop flights from Boston to San Juan?
The current cheapest fares involve a connection, ticketed under Frontier Airlines. Nonstop options exist on many dates at higher prices — check the live search for your exact dates.
Are these prices guaranteed?
No — these are cached fares found on real searches (this one on September 1). Airlines reprice constantly, so the booking search re-checks the live price before you pay. Fresher finds are far more likely to still be available.
Next step
Sleeping in San Juan?
Lock the flight first — then compare stays for Sep 24 – Sep 27 · 3 nights.
Browse hotels ↗
Missed it?
Cached fares expire. This route has a feed of its own — follow it and the next BOS → SJU drop reaches you as soon as we find it.
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