See bottom of article for info on passes.
Lisbon has four main public transportations: Bus (run by Carris, also includes trams, funiculars and the Santa Justa Elevator), Metro, Train (with CP and the private compnay Fertagus and ferries across the river.
Buses, Trams & Funiculars
Carris was founded in 1872 and their trams became one of the main symbols of the city. They were the main mean of transportation until the 1960's when the Bus and Metro networks started the trams' slow decline.
Today there is an extensive network of buses, trams and funiculars in Lisbon, and they are all worth a ride on, especially the vintage trams, and the funiculars. They are an attraction in themselves.
Despite the foreigner common knowledge of Lisbon being a "city of trams", there is only about 1/6 of the former route lines and the total network is four times smaller. The remaining routes connects the hills of southern Lisbon and the nº 15 tram covers entirely the Lisbon's Tagus southern margin from downtown to the city's most southern-west point at Algès.
The bus network covers the entire city including the airport and also serves certain areas outside the city and located in other Municipalities, like Cruz Quebrada, Linda-a-Velha, Alfragide, Odivelas and Prior Velho, among a few others.
There is a very good unofficial map of the five remaining tram routes at http://www.urbanrail.net/eu/pt/lisboa...
Here is the official and up-to-date map on the Carris website also there are 'spider' maps of areas where many routes intersect.Note that there are separate maps for daytime and night-time bus networks.
Also look at individual bus lines (which includes the trams) for the stops along the line. Carris' network map is more oriented to Lisboans than visitors but can be useful if also looking at a good city map.
See the article on Tram 28 in the "Things to Do" attractions section. It is a very popular way to see the old district on the hill where Castelo do Sao Jorge is located.
Metro
Lisbon's Metro was inaugurated in 1959 and the network has more than doubled their size in the last 15 years but still has much to grow to cover the entire city. No works are currently in progress although several are planned for future years.
Is the quickest way to travel to some areas and there are four lines. All lines operate from 0630am to 1am every day. The metro is the least expensive and for many the quickest way between the airport and city centre.
Head for Baixa-Chiado or Restauradores stations for the old and historical parts of the city centre. There is also interesting architecture and tilework in the stations, so is an attraction in itself. Beware however of pickpockets. Written and audio warnings in both Portuguese and English can be found in most stations, but this will not protect you from theft attempts. Most stations have no visible staff presence.
More information about the network can be found on the Metropolitano de Lisboa website. This is a useful website as you will be able to obtain more detailed maps around each station with bus and tram routes included. A 24 hour pass costing 6 Euros can be obtained from the stations and will allow travel on the cities' buses, trams, funiculars and metro for 24 hours. Note that the ticket costs an extra 50 cents but can recharged - don't throw it away!
Train
Lisbon has several train stations and a network that serves national, regional, suburban and urban areas. Check CP official site
for more information and to purchase tickets. Also for the trains that cross the river to the southern suburbs see http:www.fertagus.pt
Boat
Because of its location along the river Tagus, Lisbon has three fluvial stations (also serving the Bus and Metro networks) connecting the city to other places located in the southern margin of the river, like Cacilhas, Seixal and Montijo among others. The "Cacilheiro" is another symbolical mean of transportation of Lisbon's Metropolitan area.
You can check out schedules, ticket prices on the Transtejo-Soflusa official website (There's still no English version but all that information is under "Horário e Tarifário" option).
Fares and Passes
Flat fare on the buses is €1,80 - cash paid on board. Flat fare on the trams (streetcars) is now 2,85 Euros with the object being to make more users buy pre-pay passes. A single ticket on the metro is €1.90 without a rechargeable card, €1,40 with.
There are a variety of passes available which reduce those costs considerably. Details are available in English on the Carris website as above. (Unfortunately the Carris website is difficult to navigate and is lacking in information.) Be aware that a rechargeable card can only hold one tyupe of ticket at one time. When empty, it can reloaded with any different tariff. Every traveller requires a ticket, they cannot be shared if traveling together.
If you are on the metro, you can transfer freely from one line to another. On the bus, however, tickets are valid for travel on a single route. If you transfer from one route to another, you have to zap your card again or pay another cash fare.
There are no senior discounts except for residents. There are no weekly or monthly tickets suitable for visitors.
The "best deal" for a visitor may be to buy the 24 hour pass for as many days as required. The cost is 6.50 Euros for the first day, and 6.00 Euros for each additional day. The ticket is isued on a rechargeable card that has be recharged each day - don't throw it away.
It is good for all buses, trams and Metro. It allows unlimited use throughout the city. It can be purchased at any Metro station and in some post office branches. It is best to see the attendant in the booth rather than try to use the automated ticket vending machines as they are confusing to some (instuctions are available in English) and do not take credit cards without chip and Pin. Do note that buying at the booth requires cash and often a very long wait for service.
The 'zapping' pass stores cash value on a rechargeable card. It does not expire with time. Each ride on metro, tram or bus is charged at €1,25, on trains €1,80. Zapping can be used to get to Sintra and Cascais by train. Zapping tickets are purchased in the same way as the others already mentioned.