Public transport[edit]
Istanbul's public transit system can be difficult to figure out; maps are rare and you often have to transfer, and pay another fare, to get where you are going. However, if you put some effort into it, you can avoid taxis and not walk too much.
There is an extensive bus system, including city-run and private buses, as well as one high-speed Metrobüs line; an extensive light rail system including four Metro (underground) lines, four Tramvays (aboveground), two Fünikülers (ascending/descending), two mini-lines called Teleferik, and the Marmaray (underwater) lines; and the ferries which travel the Bosphorus.
An important supplement to all of this (particularly late at night) is the fleet of private dolmuş minivans, which follow prescribed routes and wait until they fill up before departing. They range in price from 2-8 lira (paid in cash), depending on how far you're going. They run all night long, unlike most of the public transport lines. So if you find yourself stranded at Taksim at 4am, a dolmuş is your way home. Look for the yellow minivans, and ask them where they're going ("néreye gidiyórsunuz?").
Each time you use a tram, metro, bus, or boat on the public transport system, you will need to use a token (expensive) or a magnetic card (cheaper, see below). The small metal/plastic tokens cost 4 TL (July 2014) and can be bought at various ticket kiosks & machines at bus, railway and metro stations. Ticket fares across buses, trams and metros are at a flat rate (i.e. not dependent on how far you go). Only cash in Turkish lira is accepted at ticket kiosks of public transport, no credit cards or foreign currency. Also be aware that the Istanbul subway system does not offer transfer tickets and as such each new line requires a new fare, unless you use an an Istanbulkart or Akbil (see below).
Istanbulkart[edit]
An Akbil device.
Buying an Istanbulkart is a good idea if you are in Istanbul for more than a day or two, and intend to use public transport. This is a plastic card that looks like a credit card. It can be used as a ticket on buses, trams, suburban trains, metro and even the cross-Bosphorus ferries. You touch the Istanbulkart to a reader when you get on the bus or enter the tram/metro platform. The great part for groups of travellers is that you can buy only one and touch it as many times as there are passengers (unlike London's Oyster card, there is no need to touch out). You can buy or refill them at designated booths located at any major bus, tram, to metro station, as well as some other places such as newspaper stands close to bus stops. An Istanbulkart provides a flat fare of 2.15TL for the first ride, which is a cheaper option in comparison to tokens used in Metro and speed trams (jeton, 4TL). It is also 3,85TL to the Prince's Islands, instead of 6TL for a token, 4,15TL to Sabiha Gökçen airport instead of 5TL. Istanbulkart also allows discounts in transfers (when used multiple times within a limited period, roughly an hour and a half since the last time you used it). A deposit for the device itself is payable when you buy it (7 TL + any top-up), which is not refundable, and neither is any credit left on the Istanbulkart (when bought at the Ataturk airport metro terminus, 4TL deposit will be already on the card when bought). Note that there are different booths for buying the card and for charging it, and charging booths accept only 5, 10, and 20 lira banknotes.
Once you have bought and loaded the card, your first journey costs 2.15TL (except for Metrobus, which costs around 3TL). Then, any change within approximately 2 hours costs progressively cheaper: the second journey is 1.45TL, the third is 1.15TL, the fourth and fifth are 0.85TL (fares accurate as of Jan 2016). When several people are traveling using one card, the fare paid for the second, third etc. passengers may differ. Note that changing metro line or travel type, i.e., ferry to bus, or metro to tram, requires you to go out of the turnstiles and then back in to the new line or travel type. Therefore, this is extremely more economical than buying individual jetons at 4TL per journey.
The Istanbulkard is relatively new, and is replacing the older Akbil metal touch-token which is being phased out (but is still in wide use). It is now just about impossible to buy an Akbil. However, there are still some places that do not yet accept the Istanbulkart, so if you have an Akbil token left over from previous trips to Istanbul, keep hold of it: they still work. Some Kiosks still have Akbil signs rather than Istanbulkart signs - but you can usually buy or top up your Istanbulkart at any kiosk where the Akbil sign is displayed.
By bus[edit]
Bus and tram, together
IETT, [3]. edit
There are two types of public buses in Istanbul; those run by the private sector and those run by the city-owned İETT. You can differentiate these two types by their colors. Privately run buses are blue-green with yello