Eurostar does not have a strict "numerical" limit on the amount of alcohol you can bring on board for personal consumption, but they do have a code of conduct regarding "moderation and safety." You are permitted to bring your own bottles of wine or beer (often described as "bubbles for the journey"), and alcohol is also served in the onboard cafe-bar. However, if a passenger behaves in an antisocial way or appears excessively intoxicated, staff have the authority to confiscate the alcohol or even ask the passenger to leave the train at the nearest station. For certain high-risk travel dates (such as major sporting events), Eurostar may occasionally implement a temporary "dry train" policy where no alcohol is allowed. Generally, as long as you are drinking discreetly and respectfully, there is no weight or bottle-count restriction for standard travelers as of early 2026.