From Innsbruck you take the Brenner Motorway to Schönberg (behind the Europabrücke Bridge). Take the exit "Stubaital". When entering Neustift, you turn right in front of the Hotel Stubaihof. After some 200 m you can see the Pension Sonnleitn on the right side.
By train:
From Innsbruck Main Station, take the bus to Neustrift. Get off at the first stop of the locality (let the driver point it out to you) and walk into the small road, alongside the Hotel Stubaihof. After some 200 m you can see the Pension Sonnleitn on the right side.