023 is not a country code. Numbers inside a country start like this: Guba (Azerbaijan), Portsmouth (United Kingdom), Chongqing (China), Zrenjanin (Serbia) 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 |
|---|---|---|
 Guba · Azerbaijan | +994 23 … | 023 … |
| Gusar · Azerbaijan | +994 23 … | 023 … |
| Khachmaz · Azerbaijan | +994 23 … | 023 … |
| 3 more in Azerbaijan | ||
 Portsmouth · United Kingdom | +44 23 … | 023 … |
| Southampton · United Kingdom | +44 23 … | 023 … |
 Chongqing · China | +86 23 … | 023 … |
 Zrenjanin · Serbia | +381 23 … | 023 … |
 Haarlem · Netherlands | +31 23 … | 023 … |
 Bamian · Afghanistan | +93 23 … | 023 … |
 Algiers · Algeria | +213 23 … | 023 … |
 Zadar · Croatia | +385 23 … | 023 … |
 Granma Province · Cuba | +53 23 … | 023 … |
 at · Ghana | +233 23 … | 023 … |
 Semnan Province · Iran | +98 23 … | 023 … |
 Bandon · Ireland | +353 23 … | 023 … |
 Yamagata, Yamagata · Japan | +81 23 … | 023 … |
 Zawia · Libya | +218 23 … | 023 … |
 Beaufort West/Karoo/Robertson/Worcester · South Africa | +27 23 … | 023 … |
 Falun · Sweden | +46 23 … | 023 … |
 Edleb · Syria | +963 23 … | 023 … |
 Coast/Morogoro/Lindi/Mtwara · Tanzania | +255 23 … | 023 … |
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.