AirHint found the following cheapest return flights from Chicago (ORD) to Lisbon (LIS) in May 2026 (see full year).

Return flights

06 May - 10 May	Icelandair
02 May - 10 May	Icelandair
01 May - 08 May	SWISS
03 May - 13 May	SWISS
04 May - 12 May	Aer Lingus
06 May - 13 May	Aer Lingus
06 May - 14 May	Aer Lingus
08 May - 15 May	Icelandair
02 May - 13 May	Aer Lingus
08 May - 13 May	Aer Lingus
05 May - 18 Jun	Turkish Airlines
25 May - 02 Jun	Aer Lingus
01 May - 18 Jun	Turkish Airlines
26 May - 03 Jun	Scandinavian Airlines
31 May - 07 Jun	Air Canada
17 May - 05 Jun	Frontier Airlines
18 May - 06 Jun	Aer Lingus
23 May - 06 Jun	Finnair
17 May - 05 Jun	TAP	direct
01 May - 18 Jun	TAP	direct

Also check the deals for one-way flights from Chicago to Lisbon 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 Chicago to Lisbon in May from 412€

Return flights