Certaldo is straightforward to reach by train. From Florence, trains run on the Florence–Empoli–Siena line and take around 40 minutes; there are frequent departures through the day. From Siena, the same line runs in the other direction, passing through Poggibonsi — the journey takes roughly 30 to 40 minutes depending on the service. The train station is in the lower town (Certaldo Basso), and the funicular up to Certaldo Alto departs a short walk away.
By car from Florence, follow the Superstrada Firenze–Siena (SGC Fi-Si) and exit at Certaldo Sud or Poggibonsi Nord — the drive takes around 45 minutes depending on traffic. From San Gimignano, Certaldo is only about 15 kilometres away by road, making the two towns natural companions for a day out in the Val d'Elsa. Parking in the lower town is straightforward; driving up to Certaldo Alto is possible but the lanes are narrow and parking is very limited.