How do I switch between virtual terminals in a guest system?

I want to access virtual consoles in my Ubuntu guests running VirtualBox with Ubuntu guest. However, even if the focus is within the guest window, if I press Ctrl+F1 thru F6 I move in a virtual terminal of the host, not the guest.

How do I switch to a virtual terminal in the guest OS?

Press Host + F1.

Host inserts Ctrl + Alt on the guest system.

The actual key on your keyboard for Host is visible in the right bottom of the VM window and can be configured.

1. Open the VirtualBox Manager
2. Open File -> Preferences
3. Open the Input tab
4. Click on the field next to Host key
5. Press the preferred key for Host
6. Save the settings by pressing the OK button

On my system, I've chosen for Right Ctrl. The Host key is also used for toggling fullscreen (Host + F).

Also for those who are running Virtual Box on Mac OS, remember to press the fn key in addition to the Host since it is the key to toggle F1 through F12 functionality on Mac OS. So the combination becomes Host + fn + F1 through F12.