London to San Luis Potosí (LHR–SLP) — Airlines, Schedules & Connections

British passport holders enter Mexico visa-free for up to 180 days. No fee, no advance application. Passport must be valid for the duration of the stay. On the aircraft or at the border, you receive a Forma Migratoria Multiple (FMM) card. The digital version is available at inm.gob.mx and can be completed before arrival.

Do not lose the FMM slip. You must return it when leaving Mexico. A replacement costs roughly MXN 600 (about $35) and involves a trip to an INM (immigration) office. Immigration officers sometimes stamp fewer than 180 days; if you need the full allowance, politely request it at the counter. No supporting documents are required beyond a valid passport.

Direct flights from London Heathrow to Mexico City (MEX) run about 11 hours 30 minutes on British Airways and Aeromexico. The Mexican peso (MXN) trades at roughly 17 MXN per $1. ATMs give better rates than exchange bureaus; avoid airport booths. No vaccination requirements for UK arrivals. Mexico City sits at 2,240m elevation, so altitude effects (headache, fatigue) hit some people on day one. Tap water is not drinkable; buy garrafones (20L jugs) or bottled water.

Heathrow Express runs from London Paddington to T5 and T2/T3 in 15–21 minutes (£37 single, cheaper booked online or via the Heathrow app). Elizabeth line (Crossrail) is a lower-cost alternative; Paddington to T5 in 34 minutes from £13.50 with an Oyster/contactless cap of £14.90. The Elizabeth line also serves central London stations including Bond Street, Farringdon, and Liverpool Street.London Underground Piccadilly line serves all terminals (T2/T3/T4/T5) from central London in 40–60 minutes (£6 with Oyster). Taxis (black cabs) from central London cost £55–90 depending on traffic. Coach services from Victoria Coach Station (National Express) cost from £10 booked in advance.