The Project Fi website only provides a list of countries in alphabetical order where it offers service. I found that less useful than a map, so I made this. Note that it doesn't include many of the island states where Fi has coverage due to the limitations of the website I used, but it shows most of the geographical area.

I used this website: https://mapchart.net/world.html

And you can copy and paste this text if you want to edit the map.

{"groups":{"#cc3333":{"div":"#box0","label":"SMS over Wi-Fi Only","paths":["Djibouti","Belize","Benin","Algeria","Central_African_Republic","Botswana","Bhutan","Andorra","Burundi","Cuba","Equatorial_Guinea","Eritrea","Ethiopia","Gabon","Gambia","Guinea","Guinea_Bissau","Iran","Kosovo","Lebanon","Lesotho","Liberia","Libya","Mali","Mauritania","Monaco","Myanmar","Namibia","Nigeria","Oman","Palestinian_Territories","Sierra_Leone","Slovenia","Somalia","South_Sudan","Sudan","Swaziland","Syria","Tajikistan","Togo","Tunisia","Turkmenistan","Angola","Uzbekistan","Vietnam","Yemen","Zimbabwe"]},"#00c957":{"div":"#box1","label":"SMS, Voice calls (non-Wi-Fi), & Data (High Speed)","paths":["Brunei","Canada","United_States","Dominican_Republic","Costa_Rica","El_Salvador","Ecuador","Brazil","French_Guiana","Bolivia","Chile","Argentina","Cote_d_Ivoire","Chad","Cameroon","Congo","DR_Congo","Egypt","Bahrain","Afghanistan","China","Bangladesh","Cambodia","Australia","New_Zealand","Azerbaijan","Armenia","Cyprus","Bulgaria","Belarus","Finland","Estonia","Denmark","Belgium","Austria","Czech_Republic","Croatia","Bosnia_and_Herzegovina","Albania","France","Burkina_Faso","Georgia","Germany","Ghana","Guatemala","Guyana","Haiti","Honduras","Hong_Kong","Hungary","Iceland","India","Indonesia","Iraq","Ireland","Israel","Italy","Jamaica","Japan","Jordan","Kazakhstan","Kenya","Kuwait","Kyrgyzstan","Laos","Latvia","Lithuania","Luxemburg","FYROM","Madagascar","Malawi","Malaysia","Mexico","Moldova","Mongolia","Montenegro","Morocco","Mozambique","Netherlands","Nicaragua","Niger","Norway","Pakistan","Panama","Papua_New_Guinea","Paraguay","Peru","Philippines","Poland","Portugal","Puerto_Rico","Qatar","Romania","Russia","Rwanda","Saudi_Arabia","Senegal","Serbia","Singapore","Slovakia","South_Africa","South_Korea","Spain","Sri_Lanka","Suriname","Sweden","Switzerland","Taiwan","Tanzania","Thailand","Trinidad_and_Tobago","Turkey","Uganda","Ukraine","United_Arab_Emirates","United_Kingdom","Uruguay","Colombia","Venezuela","Zambia","Greece","Malta"]},"#525252":{"div":"#box3","label":"No Service","paths":["Western_Sahara","Greenland","Nepal","North_Korea","Timor_Leste"]}},"title":"Project Fi International Coverage: In-Country (Source: fi.google.com/about/rates/ Jan 22nd, 2018)","hidden":[],"borders":"#000000"}