Shannon to Houston (SNN–IAH) — Airlines, Schedules & Connections

Irish passport holders enter the United States visa-free under the Visa Waiver Program (VWP) for stays up to 90 days. An approved ESTA (Electronic System for Travel Authorization) is required before boarding. The ESTA costs $21, is valid for 2 years or until the passport expires (whichever comes first), and covers multiple entries. Apply at esta.cbp.dhs.gov at least 72 hours before departure, though most approvals come within minutes.

Passport must be an ePassport (biometric chip, all current Irish passports qualify). No supporting documents are formally required for ESTA approval, but CBP officers at the port of entry may ask for proof of onward travel, accommodation details, and sufficient funds. The 90-day VWP stay cannot be extended and does not allow a change of immigration status. If you need more than 90 days, apply for a B-1/B-2 visa at the US Embassy in Dublin (MRV fee $185, interview wait times vary from 1 to 6 weeks).

Direct flights from Dublin to the US serve New York (JFK/EWR), Boston, Chicago, Washington Dulles, Los Angeles, San Francisco, and several others, running 7 to 10 hours. Shannon also has direct US routes. US Customs and Border Protection preclearance operates at Dublin and Shannon, meaning you clear US immigration before boarding and arrive as a domestic passenger. The US dollar is the only currency. No vaccination requirements for Irish arrivals.

No direct rail from IAH. The METRO bus 102 (IAH Express) runs to downtown Houston's transit center (60–90 min, $1.25). Taxis to downtown Houston cost $50–70. Ride-hails pick up at the designated Rideshare zones outside baggage claim on the lower level.IAH has five terminals (A–E) connected by an underground tunnel with trams. Terminal D handles international arrivals. Rental car agencies are in a consolidated facility adjacent to Terminal C; a free IAH Connector bus runs between terminals and the rental car center. The Galleria / Uptown area costs $35–50 by ride-hail.

Humid subtropical climate. Hot, humid, and wet for much of the year. Summers are brutal (33–38°C) with high humidity and near-daily afternoon thunderstorms. Severe storms with hail and high winds regularly cause ground stops from April through September. Houston's flooding risk is significant. Heavy rain events, including tropical system remnants, have flooded airport roads, cutting off surface access even when the airport itself remains operational.

Winters are mild (5–18°C) with occasional ice storms. These are rare but highly disruptive when they occur. Hurricane season (June–November) requires monitoring for Gulf storms. October through March has the best flying weather.