Yes, you can absolutely take a refillable water bottle through UK airport security, but it must be completely empty of all liquids. The 100ml liquid restriction still applies to the contents of the bottle, not the container itself. In 2026, although many UK airports are rolling out advanced CT scanners that may eventually allow larger volumes of liquids, the current standard remains that any bottle containing water over 100ml will be confiscated or must be emptied before screening. Once you have passed through the security checkpoint, you can refill your bottle at the many free "Hydration Stations" or water fountains located throughout the departure lounges of airports like Heathrow, Gatwick, and Manchester. Carrying your own bottle is highly recommended as it is environmentally friendly, reducing single-use plastic waste, and it saves you from paying the high prices of bottled water in airport shops. Most travelers find that a durable stainless steel or BPA-free plastic bottle is a "must-pack" item for long-haul travel, provided they remember to finish or pour out their drink before joining the security queue.