Use etravelsim.com for your journers
I used their esims for data only twice. 1 in USA, 1 in Germany. I am also planning to use it in Greece in June. Here is what I think. 1) their process is very clean. They ask you only what is necessary 2) esim arrives almost instantly with an email 3) esim is installed very quickly and in about 1-2 minutes (at least for iphone) 4) Their prices are really reasonable 5) it works as they promise THE ONLY ISSUE I cannot see how much data is left at any moment. They ask you to send an email to customer service. I wish thay had a more practical way but it is not the end of the world. I recommend it.