The café's computers, connected to BT's global IP network, will be able to download data at speeds of up to 100 Mbit/s - between 25 and 50 times faster than a typical broadband circuit.
Visitors to the satellite earth station, which attracts more than 80,000 people a year, will be able to use the superfast facilities of the internet café free of charge.
Adrian Hosford, director of Corporate Responsibility for BT, who will host the launch, said: "Connected to the network of the future, what we believe is the world's fastest internet cafe will allow people to experience for themselves online speeds, which are part of a future enabling us to do all things differently.
"For example, it would be possible to use the cafe's computers to download in less than 15 minutes a file the equivalent size of the DVD version of the Encyclopaedia Britannica - with its 19,000 illustrations, 629 audio and video clips and 100,000 articles. A standard broadband connection would typically take in excess of five hours.”
Goonhilly Satellite Earth Station is the largest station of its type in the world with 60 antennas handling thousands of international phone calls, TV broadcasts and data.
It is also the world’s oldest surviving satellite earth station. The first antenna, known as Arthur, was built to track the Telstar satellite and received the first live transatlantic television broadcasts from the United States in 1962. Arthur today is a grade II listed building and is still in operational service.