Volunteering for a cause you're passionate about is a great way to enjoy retirement, but not everyone is able to get out and about. Older adults with mobility challenges, who may need flexibility, or who must stay at home to care for a spouse or other loved one can still find fulfillment with online volunteer opportunities. Some people may simply prefer online volunteering.

The benefits of volunteering are many, including having a sense of purpose and fulfillment from helping others. Research suggests that volunteering may also be good for your emotional and physical health.

People over 50 who volunteered more than 100 hours a year — roughly eight hours a month — over a four-year period had a reduced risk of mortality and depression and enjoyed a more optimistic outlook on life, according to a study published in the American Journal of Preventive Medicine.

If you'd like to volunteer online, here are five online volunteering opportunities to get you started.

1. Help the American Cancer Society Save Lives

As a virtual volunteer with the American Cancer Society, you could share life-saving information about cancer advocacy and fundraising needs on social media and other online platforms. Maybe you'd like to email state legislators and U.S. Congress members about making cancer a nationwide priority. You can even participate in a virtual version of Relay for Life, a major cancer fundraising event.

For a full list of volunteer opportunities, visit the American Cancer Society's online volunteer opportunities.

2. Give Homeless Pets a Better Life

You may have assumed that you'd need to visit shelters to help homeless pets. But many animal rescue organizations also have online volunteering opportunities. For example, Best Friends Animal Society has online volunteering opportunities for homeless pet shelters and rescue groups around the country. You could be a foster mentor, answering questions from people fostering cats or dogs waiting for adoption. You might enjoy promoting homeless pets to potential adopters on social media and other online platforms.

Visit Best Friends Animal Society or local animal shelters for available online volunteering opportunities.

3. Mentor At-Risk Youth

Want to guide at-risk high school and middle school kids toward college and other paths that will enrich their lives as they head into adulthood? Organizations such as Be A Mentor, iCouldBe and A Family for Every Child offer online volunteer opportunities to mentor kids facing adversity around academic goals. To locate other volunteer opportunities, type "online mentor volunteer" and "at-risk youth" into a search engine or contact local organizations about online volunteer opportunities.

4. Counsel LGBTQ Youth

Acceptance from even one adult can lower the risk of suicide for lesbian, gay, bisexual, transgender, queer and questioning (LGBTQ) young people by 40 percent, according to The Trevor Project, an organization dedicated to suicide and crisis intervention for LGBTQ youth. Remote volunteers answer calls, chats and texts from LGBTQ young people seeking support for identity- or gender-related challenges. Over the past year, volunteers for The Trevor Project answered more than 200,000 calls, chats and texts.

Visit The Trevor Project to apply for an online volunteer position.

5. Assist with Disaster Recovery

If you admire the boots-on-the-ground efforts of the American Red Cross, don't assume you can't help this worthy organization unless you're at the disaster scene. You can volunteer for the American Red Cross as a virtual volunteer, too. Online volunteer opportunities include helping families with recovery planning and casework after a home fire. Or you may want to become a digital advocate, promoting the American Red Cross's efforts and fundraising on Facebook, Twitter and other social media platforms.

Visit the American Red Cross's Become a Volunteer page to explore more online volunteer opportunities.

How To Get Started

If you're eager to begin volunteering online, check out the above opportunities. But you don't have to stop there.

Search through the many online volunteer opportunities for the best way you'd like to help others. Start with VolunteerMatch, where you'll find hundreds of online volunteer opportunities. Call or visit the websites of organizations with causes you're passionate about.

Before you know it, you'll be well on your way to fulfillment through virtual volunteering.