Greece
Greece seems to have a really good range of writing retreats at varying prices and at flexible times of the year. The ones listed below are the ones I've found that look most enticing and are affordable.
Liminisa Retreats
This idyllic-looking retreat is one of the ones I am keenest to try. It has a private beach and a range of affordable accommodation options, including private studio flats.
Mostly untaught, there are opportunities to share work with others. Vegetarian food provided. The owners are friendly to deal with and responsive.
Retreats take place in summer and winter and an annual competition to win a place.
If you've been to Limnisa, I would love to hear about it so please message me.
Full information here.
Skyros Writing Holidays and Retreats
The Writers Lab at Skryos hosts 7 or 13 night retreats between May and September in Skyros. Courses have a range of themes including: How To Write Funny and Starting to Write Fiction. They are open to all writers and are affordably priced.
If you've been on one, I would love to hear about it so please message me.
Full information here.