AirHint found the following cheapest return flights from Boston (BOS) to San Juan (SJU) in October 2025 (see full year).

Return flights

03 Oct - 05 Oct	Frontier Airlines
02 Oct - 05 Oct	Frontier Airlines
16 Oct - 19 Oct	Frontier Airlines
10 Oct - 12 Oct	Frontier Airlines
17 Oct - 19 Oct	Frontier Airlines
09 Oct - 12 Oct	Frontier Airlines
23 Oct - 26 Oct	Frontier Airlines
04 Oct - 09 Oct	Frontier Airlines
05 Oct - 17 Oct	Frontier Airlines
24 Oct - 26 Oct	Frontier Airlines
29 Oct - 05 Nov	Delta	direct
23 Oct - 10 Nov	Spirit Airlines
26 Oct - 10 Nov	Spirit Airlines

Also check the deals for one-way flights from Boston to San Juan in October.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

Book a cheap hotel in San Juan

Cheap car rent in San Juan

Cheapest return flights from Boston to San Juan in October from $168

Return flights