Volunteer opportunities in Portugal

For a retired single like me it is important to be able to quickly become part of a community.  I moved 3 years ago to a city where I did not know a soul and was able to quickly make friends through church and volunteer activities.  My present volunteer activities include a group building a house for homeless working families in our area, talks on healthy aging and dementia prevention for senior oriented community college, a group building houses and other infrastructure in Guatemala, a group that puts together Christmas gifts for impoverished seniors, singing in the church choir and other.  Are volunteer activities for English speakers readily available in Portugal?  Thinking about Algarve or Atlantic coast in viciinty of Porto.