028 is not a country code. Numbers inside a country start like this: Antrim (United Kingdom), Chengdu/Ziyang/Meishan, Sichuan (China), Kosovska Mitrovica (Serbia), Alegre - ES (Brazil) and others. The first digit 0 is the trunk prefix for domestic calls and is dropped from abroad.
Have the full number? Check it in the number lookup.
| Area or operator | From abroad | Inside the country |
|---|---|---|
 Antrim · United Kingdom | +44 28 … | 028 … |
| Armagh · United Kingdom | +44 28 … | 028 … |
| Ballycastle · United Kingdom | +44 28 … | 028 … |
| 32 more in United Kingdom | ||
 Chengdu/Ziyang/Meishan, Sichuan · China | +86 28 … | 028 … |
 Kosovska Mitrovica · Serbia | +381 28 … | 028 … |
 Alegre - ES · Brazil | +55 28 … | 028 … |
| Anchieta - ES · Brazil | +55 28 … | 028 … |
| Apiacá - ES · Brazil | +55 28 … | 028 … |
| 34 more in Brazil | ||
 Panjshar · Afghanistan | +93 28 … | 028 … |
 Algiers · Algeria | +213 28 … | 028 … |
 Expresso · Ghana | +233 28 … | 028 … |
 Qazvin Province · Iran | +98 28 … | 028 … |
 Skibbereen · Ireland | +353 28 … | 028 … |
 Utsunomiya, Tochigi · Japan | +81 28 … | 028 … |
If a number starts with +, the first 1–3 digits are the country code. If it starts with 0 (8 in Russia and Kazakhstan), it is a domestic number: an area or operator code follows, and from abroad the 0 or 8 is replaced with + and the country code. The same digits can mean different places, so where the call came from matters.