At London Heathrow, whether you can drop your bags off early depends entirely on your airline's specific policy and the terminal you are using. Generally, most airlines allow bag drop starting 3 hours before a long-haul flight and 2 hours before a short-haul flight. However, some major carriers like British Airways at Terminal 5 offer more flexibility. For BA flights departing before 1:00 PM, you can often use the "Overnight Bag Drop" service to check your bags the evening before between 4:00 PM and 9:00 PM. For same-day early arrivals, BA usually allows bag drop from the moment the desks open at 5:00 AM, regardless of your flight time later that day. Other airlines, especially low-cost carriers or those using shared desks in Terminal 2 or 3, may strictly enforce the 3-hour limit to manage terminal congestion. In 2026, Heathrow is increasingly utilizing "Self-Service Bag Drop" kiosks to speed up the process, but these will still reject your tag if you are too far ahead of your "departure window." If you arrive much earlier than 3 hours and your airline won't take your bags, you will need to use the "Excess Baggage" storage facilities located in the landside areas of each terminal for a fee.