From London, which is easily accessible, National Express and iDBus offer a combined 11 direct routes to Paris, France; from there you can easily get a bus to Madrid, Spain, where there are plenty of buses available going to Lisbon. If you'd rather stop somewhere else in Spain, there are also direct routes from smaller cities, such as Badajoz just on the Spanish border. The main carrier going into the city is Avanza, which is a Spanish service. In the city, passengers are dropped at Estacao Do Oriente, which isn't directly in the city center, but is incredibly close to the airport and Lisbon's metro, allowing you to easily travel into the city center and see the town's sites.
An excellent city to visit all year round, Lisbon is well known for its mild climate and inexpensive prices compared with many of Western Europe's other capitals. However, this city's draws go well beyond its convenience. Lisbon's rich history makes it the second oldest European capital, following only Athens. This means that the city has both incredible sites and fascinating museums, including the Calouste Gulbenkian Museum, with stunning works of ancient art from around the world, and the Maritime Museum, which focuses on the city's massive role in the Age of Exploration. Also, be sure to visit the architectural examples of Lisbon's history, including the intricate Jeronimos Monastery, the Belem Tower and São Roque Church, which was once the most expensive chapel in the World. There are also absolutely beautiful beaches, featuring turquoise blue waters and golden sands, and all the incredible shopping opportunities you'd expect from Portugal's largest city. Add that to the excellent culinary offerings and a lively nightlife and you have a holiday fit for anyone!