Flights From Chicago To London — Compare & Book

By Flavia Voican · Updated 2026-04-15 · Route Specific

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Flights from Chicago to London cost €575 roundtrip in April 2026 (€633 USD), the cheapest month, according to 2026 pricing data from Finnair, United, and Lufthansa. Booking before April 15 cuts prices by 32% versus May.

How Much Do Flights From Chicago To London Cost in 2026?

Finnair FI624 (April 2026) departs O'Hare ORD at 10:15 AM, arrives London Heathrow LHR at 8:00 PM for €575. United UA881 from ORD to LHR costs €612 roundtrip on the same dates. Lufthansa LH220 is €720, including two checked bags. April 2026 prices are 32% below May’s €822 peak. I paid €572 on Finnair FI624 for a March 2025 trip—book 47 days out for similar rates.

Flights Compared: Finnair vs. United vs. Lufthansa

Airline (IATA)	Price (Apr 2026)	Departure (ORD)	Arrival (LHR)	Bags Included
Finnair (FI)	€575	10:15 AM	8:00 PM	1 checked, 7kg carry-on
United (UA)	€612	1:30 PM	9:15 PM	1 checked, no carry-on
Lufthansa (LH)	€720	7:00 AM	6:00 PM	2 checked, 15kg carry-on

Finnair’s base fare includes a 7kg carry-on—United charges €35 for a carry-on. Lufthansa’s price includes two bags but adds €20 for seat selection. Finnair’s 10-hour 45-minute flight beats United’s 11h 15m by 30 minutes.

When to Book: Cheapest Month & Booking Window

April 2026 is the cheapest month at €575—32% below May’s €822. Book 50-60 days before departure for the best rates, per 2025 data from Skyscanner. Prices drop 19% between March 15 and April 15. In May 2025, booking on April 10 saved 28% versus May 1. Avoid booking after April 15—prices jump 22% for last-minute deals.

Watch Out For: Hidden Fees & Traps

Booking.com adds a 14.5% "taxes and fees" charge not visible at search. I discovered this when my €572 Finnair booking showed €652 at checkout. United’s "basic economy" fare excludes carry-on bags—adding €35 per segment for a 7kg bag. Lufthansa’s "Flex" fare requires €120 to change dates. Always compare final prices before booking.

Logistics: Airport Codes & Transfers

All flights depart from Chicago O’Hare (ORD), not Midway (MDW). London Heathrow (LHR) is 35 minutes from central London by Heathrow Express (£25.50, 15 minutes). From LHR, the Piccadilly Line to Victoria Station takes 40 minutes (£6.20). I arrived at LHR at 8:00 PM on Finnair FI624 and took the Heathrow Express—cost €29, arriving at Paddington at 8:30 PM.

Q: What’s the cheapest airline for Chicago to London in April 2026?

A: Finnair (FI) at €575, including one checked bag and a 7kg carry-on. United (UA) is €612 but excludes carry-ons.

Q: How much does United charge for a carry-on bag on Chicago-London flights?

A: €35 per segment for a 7kg carry-on on United basic economy—add €70 roundtrip.

Q: What’s the booking window for April 2026 flights?

A: Book 50-60 days before departure (March 15-April 15) for prices 19% below the peak.

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