Zubarah is about 105 km north of Doha via the main highway to Al Shamal. The drive takes around 90 minutes. There is no public transport; a car is essential. The road is well-surfaced and straightforward — follow signs for Al Shamal, then look for the brown heritage signs to the fort and archaeological site near the town of Al Zubarah. Parking is free at the site entrance.
Some tour operators in Doha run day trips to Zubarah, often combined with visits to Al Khor or a desert picnic lunch. These are worth considering if you don't have a vehicle, though the cost is significantly higher than self-driving.