This does not apply only to bookmarks, but if you want to transfer bookmarks and other settings, you will want to copy the settings file from:
~/Library/Preferences/iTerm.plist ~/Library/Preferences/net.sourceforge.iTerm.plist
from existing setting / account:
~/Library/Preferences/net.sourceforge.iTerm.plist
iTerm.plist is an old location and is used by some versions of iTerm. The new location is net.sourceforge.iTerm.plist.
source share