Mr Peake and his two colleagues, Russian Yuri Malenchenko and American Tim Kopra, were welcomed with hugs from the ISS's existing crew members after successfully docking their Russian Soyuz spacecraft,
The former Army major and helicopter pilot has not stopped smiling all day. Here's his amazing journey - in pictures:
British astronaut Tim Peake is on board the International Space Station, six-and-a-half hours after blasting off from a base in Kazakhstan.