The NauticEd Bareboat Charter Clinic course deals with VHF licenses for chartering in the Mediterranean. Module 4 discusses the use of the VHF covering such things as: appropriate non-commercial channels for different countries, appropriate language,  the phonetic alphabet, emergency hailing, non-emergency hailing, the channel reserved for DSC, broadcast distance, and power.

Once complete the software will award a VHF endorsement on your certificate mostly this is sufficent. 

However, we also advise that you gain a government VHF operators license from your home country which will be respected in the country you are visiting. This acts as insurance in case there is a particularly stubborn port authority. The last thing you want is to be held up from chartering at the last minute. This is particularly the case in Croatia. Nothing is required for the Caribbean.

In Canada - you should gain the ROC-M

In the USA you should gain the FCC VHF license. 

Module 4 of the NauticEd Bareboat Charter Clinic course details how you gain these additional government licenses.