Janisławiec was formerly part of the German Empire. In the German Empire, the place was called Johannisthal.
The place is now called Janisławiec and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Johannisthal | German Empire | Lauenburg i.Pom. | 1939 |
| Janisławiec | Under Polish administration | Lębork | 1945 |
| Janisławiec | Poland | Słupsk | 1992 |