AirHint found the following cheapest return flights from Denver (DEN) to San Juan (SJU) in May 2026 (see full year).

Return flights

13 May - 16 May	Frontier Airlines
02 May - 16 May	Frontier Airlines
05 May - 12 May	Frontier Airlines
07 May - 11 May	Frontier Airlines
07 May - 18 May	Frontier Airlines
01 May - 09 May	Frontier Airlines
12 May - 15 May	Frontier Airlines
01 May - 10 May	Frontier Airlines
10 May - 10 May	Frontier Airlines
27 May - 03 Jun	Frontier Airlines
26 May - 03 Jun	Delta
07 May - 18 May	United	direct
27 May - 03 Jun	United	direct
26 May - 03 Jun	United	direct

Also check the deals for one-way flights from Denver to San Juan in May.

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.

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Cheapest return flights from Denver to San Juan in May from 168€

Return flights