Estoril is a residential area and apart from the casino there is nothing to do there. A lovely promenade joins the two resorts and it is a pleasant walk between the two. We stay at the Pica Pau in Estoril (see reviews on this site)which I can thoroughly recommend and walk to Cascais along the prom and then get a taxi back (under 5 euros). There is a station at both Estoril and Cascais and the jopurney into Lisbon is approx 25 mins, is cheap and a great ride all along the coast. There is also a bus service from both resorts to Sintra, the world heritage site in the mountains with palaces and castle and traditional town to see. Look in the Lisbon forum as well for information on Cascais/Estoril.
Estoril is a stylish and fashionable Portuguese beach resort that is situated on the beautiful coastline that extends to the west of Lisbon. Estoril strikes the perfect balance between Portuguese charm and excellent tourist facilities, to create the ideal destination for those tourists who want more than just great beaches for their holiday. The town boasts fine restaurants, world-class hotels and the largest casino of the Iberian Peninsula, all of which provide Estoril with a prosperous atmosphere and a reputation for exclusivity.
Cascais and Estoril are connected to Lisbon by a regular (departures every 20 minutes) and inexpensive (€2.20 adult single) train service which also makes transfers from the airport relatively easy and inexpensive. Accommodation in both towns fills up quickly during the summer months, so it is advisable to book hotels well in-advance.
Estoril is quite small, you can go to the beach, surf, bike, walk, go to the casino but you should absolutely go to other places.
Estoril has an elegance more commonly attributed to resorts on the Côte d’Azur. Exiled royalty and deposed despots made this their haven during World War II, alongside spies from both sides. During a stay at the famous Palácio Hotel, Orson Wells apparently expressed amazement at the number of monarchs also in residence. Only a short train ride out of Lisbon, Estoril and its neighbour Cascais also make for an excellent day trip if visiting the capital.
I live in Estoril. Visit Cascais, the center of a close by villa. Is really nice, and the bay too. the Guincho beach is gorgeous, although if you're unlucky, it can get really windy. There is also the Sea Wall that starts in Cascais, which has 3km of beaches, bars and restaurants along the waterfront. Very trouristic place. The Cascais marina area is also nice , with a really nice park across the road and has cycling lanes that go from the marina to Guincho beach. The Casino and its gardens are also pretty nice to see and visit. But if you can, i would also suggest a visit to the town of Sintra, which is pretty close by car, and is also gorgeous. And obviously Lisbon! Hope it helps, have fun here!
PS: sorry for the english!
A pleasant beachfront promenade links Estoril to attractive Cascais passing by beaches along the way, and frequent trains connect it to Lisbon.