From the center of Lisbon, drive to Alcântara, where you need to cross over the train lines and follow Belém's direction. After Belém's tower, keep driving with the train lines at your right side until you reach a roundabout. Take the first exit, where you'll see the heliport sign. Drive until a deviation to the Nautical Center / Heliport and then follow the road to the VTS Tower.
From Cascais, through the Marginal (waterfront road), after the exit to Algés, but staying on the same road, take a right turn that crosses over the train lines. Go straight until you see Belém's tower at your right. Make a U-turn at the following traffic lights and drive until you reach a roundabout. Take the first exit, where you'll see the heliport sign. Drive until a deviation to the Nautical Center / Heliport and then follow the road to the VTS Tower.