There is never a problem about Internet and wifi in cities, hotels and business centers. And the good news is WiFi is free for a few hours use. Guests are even provided with computers while you are inside. But networks be likely to be weak and feeble if you travel to the remotest part of the country.
Purchasing a local SIM card for your smart phone or iPad will give you connectivity outside the hotels or when you are travelling. Reactivated 3G/4G Bhutanese SIM cards are available at a SIM counter located in the post office (to the right of the terminal exit door) at Paro Airport. The cost for the SIM is approximately US$2.00 plus call credits.