Link-based access is great when you need to share information from your calendar with a larger group of people. For example, you may want to share a read-only link of a group calendar with all group members, so they can see upcoming events. Or you send an add-only link so that people can reserve a meeting room at a co-working space. 

Using a shareable calendar link is helpful in these situations because it is simple, easy to use, and no one has to create an account or log in to access the calendar. 

However, the link may be shared outside of the group with people who should not be able to use it. Or, over time, members might leave the group or no longer be part of the shared space. So you want to keep the link secure and used only by currently authorized people. 

Here are two approaches. 

Add a password to the calendar link

You can add password protection to a shareable calendar link (available on paid subscription plans). Then share the password only with the current group members. 

Periodically, you can change the link password and share the new password again to keep the link secure. 

Change the link regularly

If you want to stay on the free plan so cannot use password protection, you can instead regularly change the link that you share with group members.

For example, every month, you could create a new shareable link and share that with only those that need access. You could name the link accordingly, e.g. "October Access Link." Once the new link is created and shared, delete the previous link so it can't be used.

Combine password and regular link change

You can also combine the two approaches above by adding password protection to the link, as well as regularly changing the link.