From Tarragona's main station, take local public transport toward Plaça dels Sedassos. Get off at the nearest stop and walk the final few minutes to the square. Check the current local connection on the day of travel.
From Torre del Pretori, walk to the nearest public transport stop and travel back to Tarragona's main station. The departure point is the tower at Plaça del Rei. Check the current local connection on the day of travel.