By car: the post code for satellite navigation is CB3 9NF. From outside Cambridge, take M11 junction 12 then follow signs to Grantchester. Note that Grantchester has very limited parking, exacerbated at weekends and on sunny days by the number of visitors. See webpage on parking.
By bus: There is an hourly bus service run by Stagecoach called T3 Tiger, which runs from the Trumpington Park and Ride (with free parking) into Grantchester. Postcode for your sat.nav: CB2 9FT . It takes just 7 minutes and is a much less stressful way of coming to Grantchester. See the bus timetable page here.
By bicycle / on foot: from central Cambridge, go to Lammas Land then go south-west into Newnham, taking Grantchester Street then Eltisley Avenue, then Grantchester Meadows until the houses end then follow the path across the meadows (the ‘Grantchester Grind’) until you reach the village. It takes 15-20 minutes to walk the path.