Article taken from android central - One of the most attractive perks for Three UK customers has been its "Feel At Home" program — the ability to roam at no extra cost in a selection of countries — mainly territories where Three already has a local mobile network. From September that list will be expanding significantly to cover 24 new territories, including major European destinations like Germany, Greece, Belgium, the Netherlands and Malta, as well as the Isle of Man and Channel Islands.
Here's a complete breakdown of the new "Feel At Home" countries, which expands the service's area to cover most of the European continent.
Isle of Man
Channel Islands (Guernsey and Jersey)
That's in addition to the 18 existing Feel At Home countries, which covers many destinations in Asia, and the United States:
Republic of Ireland
The fact that the new list kicks in from September means holidaymakers traveling this month will miss out on free roaming in these countries. Nevertheless, bringing most of Europe into the "Feel At Home" zone makes sense ahead of the looming abolition of roaming charges within the EU, set to kick in from June 15, 2017.
This does not apply on the new essential plans!
Edit As per above All plans apart from the Essential Plan and with Pay as You GO users the All in Addon is required same as it currently is from what ive read.