Online resources such as Global Volunteers (www.globalvolunteers.org/portugal), Go Abroad (www.goabroad.com) and Transitions Abroad (www.transitionsabroad.com) list opportunities for volunteers in Portugal – including teaching English and helping out on social projects.
World Wide Opportunities on Organic Farms (WWOOF; www.wwoof.pt) sometimes has opportunities in Portugal. In exchange for your volunteer help, you'll receive food and lodging, and learn about organic farming as well.
The most likely kind of work you will be able to find is teaching English, if you have Teaching English as a Foreign Language (TEFL) certification. If you’re in the UK, contact the British Council, or get in touch with language schools in the area where you want to teach as possible avenues of work.
Bar work is a possibility in the Algarve, particularly in Lagos; ask around. You can also try looking in the local English press for job ads.
If you’d like to spend more time in Portugal than a vacation allows, experiencing what it’s like to live and make a difference to the local community, it’s all possible by Teaching English as a Foreign Language (TEFL) with i-to-i TEFL. No previous teaching experience or local language knowledge is necessary. Get your free i-to-i TEFL e-book now to find out more about TEFL, what TEFL jobs are available and how it can get you exploring the globe...