In case you are arriving by plane - the distances from nearest airports to Žabljak are:

If you are arriving by car, we recommend leaving it in Žabljak, there is enough parking space in the center. 

For all tours it is best to have your own car, rent a bicycle or choose a walking tour of National park Durmitor.

From Žabljak you can easily find Black Lake, by taxi or by foot - since it's only a 2.5km walk. 

If you prefer to make your own transportation arrangements to reach Black Lake, you can use GPS - it will take you straight to the starting point. Keep in mind that parking space is limited.