Most telephone numbers in Taiwan looks like this: (02) 1234-5678. The number in parentheses is the area code, usually 2 digits long but sometimes can be 3 or 4 digits. You need to dial area code if you are calling from a telephone number of different area code, or using a Cellular Phone. Local phone number is usually 6~8 digits long.
Some numbers that you may want to know:
119 is call for fire and ambulance, while 110 is call for police.
104 is for telephone directory assistance, while 106 offers telephone directory assistance in English. Please note that these numbers are not free.
Numbers start with "0800" are toll free numbers which the caller does not need to pay.
Numbers start with "0204" or simply "020x" are special numbers that charge a higher (usually much higher) rate than normal phone calls. They are mostly used in "adult services".
Except for some remote areas, cellular phones can be used almost everywhere in Taiwan. Unlike some countries, incoming calls are free in Taiwan. So it's possible to use cellular phones as a basic communacation tool without paying much.
It's important to note that, when calling a landline, the area code is always dialed first, which means all calls to landline are considered as long distance calls and charges the same, high price. On the other side, when calling numbers of the same service provider, the fare is usually much cheaper, sometimes even free! So it will be a good idea to use the same service provider of your family/boyfriend/girlfriend etc.
All cellular phone numbers start with 09xx, followed by 6 digits.
The two big operators are Chunghwa and Taiwan Mobile. Taiwan Mobile offers unlimited data with 600 NTD SIM. User chooses how many days to get mobile data, 3/4/5/7. If multiday package is not desired, unlimited data for one day is 100NTD.
Alternatively, before you leave to go to Taiwan you can opt to purchase OneSimCard if you have an unlocked GSM phone. It is a prepaid service that offers coverage in over 200 countries, including Taiwan. If your trip will be relatively short, they also provide renting options as well (this option is only available for individuals in the US). This is a great way to stay in touch with your friends and family around the world!
In Taiwan, telephone is a common media of scam. One common scenerio is that you found a missed call record on your telephone. You don't know who is it so decided to call back. Only to found a astronomical figure appears in your next telephone bill! The telephone system in Taiwan is quite complex, and left many "holes" to be cheated at. It's possible that a phone number looks normal, but is actually redirected to a paid phone that charges as much as 500 dollars per minute. It's a common sense to refuse calling back numbers unless it's from someone you know.