Satellite phones are illegal in several countries that believe they could be used by militant groups or to transmit sensitive information gathered through espionage. This includes China, Pakistan, Cuba, Russia, Chad, Myanmar, Bangladesh, Libya, areas of Nigeria, and India. Specific laws and regulations vary (for example, you can obtain a permit to use a sat phone in India and Cuba, but will be arrested, no questions asked, in Libya or Chad).
To be safe, consult the embassy of the region you are looking to travel to with a satellite phone before doing so to ensure you aren’t absentmindedly breaking any laws (or strongly held traditions).