While the Google Maps app for mobile devices does not let you map multiple locations, you can do so using the My Maps feature on the Google Maps website. Once you've created your map on the website, share it with other computers and mobile devices.
If you don't need to share the map with a mobile device, use the Google Maps website without creating a custom map using the My Maps feature.
Create the Map Using the Google Maps Website's My Maps Feature
Visit the Google Maps website, click the Sign In button in the top-right corner of the window and sign in to your Google account. You need to be signed in in order to use the My Maps feature to create a custom map with multiple locations.
Click the My Maps link located beneath the Search box in the top-left corner of the window to create a new map.
Click Untitled Map and enter a name and description for your map using the fields on the pop-up dialog.
You must enter a name and description in order to be able to share your map. Click the Save button when you're finished.
Enter your first location in the Search field and then click it on the list of search results to display it in the main map window.
Click the Pin icon located beneath the Search field and then click on the map where you want to mark your first location.
Enter an identifying name for the location using the provided pop-up window and then click the Save button.
Repeat this step until you've added all of your desired locations to the map. If locations aren't close to one another, use the Search field to quickly locate and zoom in on the location in order to pin it.
Share the Map with Your Mobile Device
Click the Share link on the left of Google Maps to open the Sharing Settings dialog.
Customize your sharing settings. Here you can select how and with whom you want to share your map. The quickest and easiest way to share a map with your mobile device is via email. Copy and paste the provided link into your email client and send it to an email address to which you have access on your smartphone or tablet.
If you use Gmail, Google Maps provides direct integration that simplifies sharing even further. Click the Gmail icon beneath the sharing link on the Sharing Settings dialog, select Anyone With Link and then click Share to Gmail.
Open your email app on your mobile device and tap the link you emailed to yourself to view your custom map with multiple locations in your mobile Web browser.
If you have the Google Maps app on your device, you may be prompted to view the map in that app instead. Both methods work.
Mapping Multiple Locations Without Using the My Maps Feature
If you don't need to share your map with a mobile device, use the Google Maps website without using the My Maps feature. This method is handy if you need to plan a driving route that passes through multiple waypoints, for example.
Enter your first location in the Search field to add it to the map and then click the Directions icon and enter your second location.
Click the Add Destination button and input your third location. Repeat this step for each location you want to add.
Click and drag the icon to the left of a location to move that location up or down on your list, changing its order on your route.