078 is not a country code. Numbers inside a country start like this: Dordrecht (Netherlands), MTEL (Switzerland), Etisalat (Afghanistan), Kyustendil (Bulgaria) 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 |
|---|---|---|
 Dordrecht · Netherlands | +31 78 … | 078 … |
 MTEL · Switzerland | +41 78 … | 078 … |
| Nexphone · Switzerland | +41 78 … | 078 … |
| Salt · Switzerland | +41 78 … | 078 … |
| 4 more in Switzerland | ||
 Etisalat · Afghanistan | +93 78 … | 078 … |
 Kyustendil · Bulgaria | +359 78 … | 078 … |
 Cellcard · Cambodia | +855 78 … | 078 … |
 Kobe, Hyogo · Japan | +81 78 … | 078 … |
 Touch · Lebanon | +961 78 … | 078 … |
 A1 · North Macedonia | +389 78 … | 078 … |
 Isabela/Quirino/Batanes/Nueva Vizcaya/Cagayan Valley · Philippines | +63 78 … | 078 … |
 MTN · South Africa | +27 78 … | 078 … |
 Hutch · Sri Lanka | +94 78 … | 078 … |
 Beeline Telecoms · Zambia | +260 78 … | 078 … |
 Econet · Zimbabwe | +263 78 … | 078 … |
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.