For a short-haul flight with hand luggage, arriving 2 hours before departure is usually enough at Heathrow. For long-haul, Heathrow advises 3 hours, and 2 hours is tight once you factor in bag drop, the morning security peak and the walk to a distant gate. If you are checking bags or flying at peak, give yourself 3 hours. Checked August 2026.
What Heathrow actually advises
Heathrow's own guidance is to arrive 3 hours before a long-haul flight and about 2 hours before a short-haul or domestic one. Those numbers exist because international departures involve more steps than a quick domestic hop: bag drop, security, sometimes a long walk to the gate, and a boarding process that closes well before departure. So the honest headline is that 2 hours is the short-haul figure, not the long-haul one.
The four things that eat your two hours
Each stage takes a different slice of the 2 hours, and the slices change with the day.
Bag drop is the first constraint. If you are checking a bag, you must reach the desk before the airline's cut-off, which is often around 60 minutes before a long-haul flight and can be earlier. If you arrive 2 hours out but spend 30 minutes reaching the terminal and finding the desk, you can still make it, but there is little slack if anything goes wrong. Travelling with hand luggage only removes this constraint entirely and is what makes 2 hours comfortable on short-haul.
Security is the second. The good news is that it is usually fast: over 97 per cent of passengers cleared Heathrow security in under five minutes across 2025, helped by the new CT scanners in all four terminals. The exception is the morning long-haul peak, roughly 05:00 to 08:00, at T3 and T5, where waits can exceed 20 minutes. If your flight is in that window, build in the extra time.
The walk to the gate is the third, and it surprises people. Heathrow's terminals are large, and some gates are in far piers or satellites a long way from the main lounge, which can be a 10 to 15 minute walk or more. Boarding, the fourth stage, then closes before departure, often 30 to 45 minutes ahead, so your usable time is less than the clock suggests.
When 2 hours is fine
Two hours is generally enough if several of these are true: you are on a short-haul or domestic flight, you have checked in online, you are travelling with hand luggage only, and you are flying outside the morning peak. In that case you walk in, clear a quick security lane and go straight airside with time to spare.
When to make it 3 hours
Give yourself 3 hours if you are flying long-haul, if you are checking bags, if you are travelling at the morning peak, if you are in a large group or with children who slow the process, or if you need special assistance. The cost of arriving early is a longer wait airside, where there are shops, food and lounges. The cost of cutting it fine is missing a bag-drop cut-off or a boarding gate, which can mean missing the flight, so the trade is not symmetrical.
Is 90 minutes enough?
Mostly no, and it's below what Heathrow itself advises. The airport's figure for short-haul and domestic is about 2 hours, so 90 minutes means you've given up half an hour of that buffer. Boarding often closes 30 to 45 minutes before departure, which leaves you roughly 45 to 60 minutes to get through the door, security and across to the gate.
It can work for hand luggage only, checked in online, flying outside the 05:00 to 08:00 morning peak, and on a gate that isn't in a far pier. Add a checked bag and it gets risky, because bag-drop cut-offs are set by the airline and can be earlier than you'd think. For long-haul, 90 minutes isn't a realistic plan.
Two hours, terminal by terminal
The two-hour advice is the same across Heathrow, but what goes wrong differs by terminal.
Terminal 5
T5 is the British Airways and Iberia terminal and carries most BA short-haul and domestic flights, so it's where the question usually comes up for a quick hop. For a domestic flight with hand luggage, 2 hours is Heathrow's own figure and normally fine. The catch is the morning long-haul peak of roughly 05:00 to 08:00, when T5 security can run past 20 minutes. If you're on an early domestic flight, that's the window to build a buffer for. Some BA long-haul routes moved to T3 from 29 March 2026, so don't assume T5 for every BA ticket.
Terminal 3
T3 is long-haul heavy: Virgin Atlantic, Emirates, Delta and the oneworld carriers, plus the BA routes that moved over from T5. Heathrow advises 3 hours for long-haul, and 2 hours here is only reasonable if you've no hold bag and you're not in the 05:00 to 08:00 peak. T3 is linked to T2 by an underground walkway, which helps if you've turned up at the neighbouring terminal by mistake.
Terminal 2
T2, the Queen's Terminal, is the Star Alliance home, including Lufthansa, United, Singapore Airlines, Air Canada and Swiss. Short-haul to Europe fits the 2-hour rule. For a Star Alliance long-haul flight, use 3 hours. Our research doesn't single out T2 for a morning security peak, but it also doesn't promise it's always quick, so the general advice stands.
Terminal 4
T4 handles SkyTeam and several Gulf and Asian carriers, such as Qatar Airways, KLM and Air France. It's on the south side and separate from the others, and you can't walk between T4 and T5 or the central terminals. Treat 2 hours as the short-haul figure and 3 as the long-haul one, and check your terminal before you leave, because a wrong turn here means a bus transfer rather than a walk.
What security is actually like
Across 2025, over 97 per cent of passengers cleared Heathrow security in under five minutes. In July 2026 Heathrow reported 98.5 per cent. Those are airport-wide figures, so they hide the early-morning peaks at T3 and T5. Security usually isn't what costs you time. Bag drop, a far gate and a wrong terminal do.
Terminal and transfer traps
Two extra things can undo a tight plan. First, make sure you go to the right terminal: some British Airways long-haul routes moved from T5 to T3 in 2026, so check your flight's terminal in advance with our guide to finding your Heathrow terminal. Arriving at the wrong terminal can cost you 30 to 60 minutes on a transfer. Second, if you are connecting rather than starting your journey here, the timings are different again, so see our guide to connection times at Heathrow.
More
More: Overview, Facilities, FAQs.
Frequently asked questions
Is 2 hours enough at Heathrow for an international flight? For short-haul with hand luggage, usually yes. For long-haul, Heathrow advises 3 hours, and 2 hours is tight once you add bag drop, the morning security peak and the walk to a distant gate. Allow 3 hours if you are checking bags or flying at peak.
How early does Heathrow tell you to arrive? Heathrow advises arriving 3 hours before a long-haul flight and about 2 hours before a short-haul or domestic one.
What time is security busiest at Heathrow? The morning long-haul peak of roughly 05:00 to 08:00 at T3 and T5 is the busiest, when waits can exceed 20 minutes. Outside that window, over 97 per cent of passengers cleared security in under five minutes across 2025.
When should I allow 3 hours at Heathrow instead of 2? Allow 3 hours for long-haul flights, when checking bags, at the morning peak, in a large group or with children, or if you need special assistance.
Do I need to worry about the walk to the gate at Heathrow? Yes. Some gates are in far piers or satellites a long way from the main lounge, a 10 to 15 minute walk or more, and boarding closes before departure. Leave time to reach the gate after security.
Is 90 minutes enough at Heathrow? Usually not. Heathrow advises about 2 hours for short-haul, and boarding often closes 30 to 45 minutes before departure. It can work with hand luggage only, online check-in and a flight outside the 05:00 to 08:00 peak, but not for long-haul or with a checked bag.
Is 2 hours enough at Terminal 5, including for a domestic flight? Yes for a domestic or short-haul flight with hand luggage, which matches Heathrow's own advice. T5 security can exceed 20 minutes in the 05:00 to 08:00 peak, so add time for an early flight, and check that your BA flight hasn't moved to T3.
Is 2 hours enough at Terminal 3? Only for short-haul or with no hold bag. T3 is long-haul heavy, and Heathrow advises 3 hours for long-haul. Its morning peak of roughly 05:00 to 08:00 can exceed 20 minutes at security.
Is 2 hours enough at Terminal 2 or Terminal 4? For short-haul, yes, as Heathrow advises about 2 hours. For long-haul from either terminal, allow 3 hours. T4 is separate from the other terminals and you can't walk between T4 and T5, so confirm your terminal first.
Is 2 hours enough if I'm checking a bag? It's tight. You need to reach bag drop before the airline's cut-off, which is often around 60 minutes before a long-haul flight and can be earlier. If you're checking a bag, give yourself 3 hours.
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Last verified August 2026 by the Heathrow Airport Guide editorial team. Prices and timetables change, so confirm the specifics on the official Heathrow Airport website before you travel.