Cambridge is well-connected by train and the station is located approximately one mile from the city centre (around 20 minutes on foot). There’s a taxi rank outside the station and buses run frequently between the station and city centre. For ticket purchases and journey planning information, see National Rail Enquiries.
The nearest airports to Cambridge are Stansted (30 miles) and Luton (40 miles). There’s a direct train link to Cambridge station from Stansted, and Heathrow and Gatwick are also easily accessible by train (via London King’s Cross/London St Pancras)
Again, it’s worth checking National Rail Enquiries for airport–train connections as it will return results including transit through London. In addition, buses regularly run from Stansted, Luton, Heathrow and Gatwick to Cambridge’s city centre (see the National Express website).