The Cacilhas Lighthouse stands at the river's edge near the ferry terminal, a modest white structure that marks the narrowing of the Tagus just before it widens into the estuary. It is not large — this was never a major maritime lighthouse in the way of coastal towers — but it is photogenic and its position right on the waterfront makes it a natural point of interest when walking along the Cacilhas front.
The lighthouse is best seen as part of a waterfront walk rather than a destination in itself. From the ferry terminal, you can walk east along the river towards the lighthouse and the naval installations beyond, or west past the Dom Fernando II e Glória frigate. The combination of the frigate, the lighthouse, and the views back across the water to Lisbon makes the Cacilhas waterfront one of the most rewarding short walks in the Lisbon metropolitan area.