Eurostar is an international high-speed rail service connecting the United Kingdom with France, Belgium, and the Netherlands. Most Eurostar trains travel through the Channel Tunnel between the United Kingdom and France, owned and operated separately by Getlink.

The London terminus is London St Pancras International; the other and since suspended British calling points used to be Ebbsfleet International and Ashford International in Kent. Intermediate calling points in France are Calais-Fréthun and Lille-Europe. Trains to Paris terminate at Paris-Nord. Trains to Belgium and the Netherlands serve Brussels-South and Rotterdam Centraal, before terminating at Amsterdam Centraal. Additionally, in France there are direct services from London to Marne-la-Vallée–Chessy (Disneyland Paris) until June 2023 and seasonal direct services to the French Alps in winter.

The service is operated by 11 Class 373/1 trainsets, each with 18 coaches, and 17 Class 374 trainsets, each with 16 coaches. The trains run at up to 320 kilometres per hour (200 mph) on high-speed lines. The LGV Nord high-speed line in France opened before Eurostar services began in 1994, and newer lines enabling faster journeys were added later: HSL 1 in Belgium and High Speed 1 in south-east England. The French and Belgian parts of the network are shared with Paris–Brussels Thalys services and TGV trains.

Eurostar is operated by Eurostar International Limited (EIL), which is owned by Eurostar Group.

In December 2021, Eurostar said it intended to move its administrative activities from London to Brussels as part of a forthcoming merger with Thalys which was approved in March 2022, citing problems with doing business in the UK and stating that being based in an EU country would make expansion and development easier.