Volunteering
Read my blog on this topic but below there are quick links to the places I've volunteered at (and had the most amazing experiences), along with their website.
Kwantu Game Reserve, South Africa - https://volunteer.kwantu.co.za
Riverside Wildlife Rehabilitation Centre, South Africa - https://www.riversidewrc.com
UpClose Bolivia, Bolivia - https://upclosebolivia.org/
Saga Humane Society, Belize - https://sagahumanesociety.org/