Hi! I think in English, you don´t say "a volunteering" but just "volunteering", without the article "a". :)

For example: "Has anybody done volunteering?"

Anyway! Yes, I have been volunteering in different organic farms in Portugal through WWOOF and Workaway. I am also registered to a website called HelpStay, and there is also another one that I'm aware of, called Helpx. You can find many potential volunteering opportunities from these!

My experiences in Portugal were mostly positive, but there are a few things to be aware of if you plan to go on volunteering. If you find an interesting-seeming host, always make sure how many hours they expect you to work in a day and for how many days a week. Think also about the location of the place you are planning to go to - for instance, if you don't travel with a bike or a car, are you ready to hitchhike in the "worst case scenario"? If so, consider about the precautions you need to take with hitchhiking and then travel remaining open-minded yet conscious of your safety! I had a positive hitchhiking experience but I also know a volunteer whose hitchhike experience was not so nice... 

Anyhow, my volunteering adventures were rich and filled with new learning experiences and beautiful memories. Different hosts have different expectations and requests so be sure to check. The websites above provide you with a list of hosts who offer you food and accommodation in exchange for help. I've done farming but there are plenty of other volunteering options than just farming. Just go to explore and I'm sure you'll find something that interests you! Good luck!

Thanks Tanja for the correction and the fantastic suggestion!! I will register on websites you mention.

Aegis of course it counts, be a volunteer in Tanzania must be a great experience.

I was a US Peace Corps volunteer for 3 years in Tanzania, Africa. Does that count?