Click the Bookmarks button
and select Show All Bookmarks to open the Library window.
From the toolbar on the Library window, click Import and Backup and choose Export Bookmarks to HTML....
In the Export Bookmarks File window that opens, choose a location to save the file, which is named bookmarks.html by default. The desktop is usually a good spot, but any place that is easy to remember will work.
Click the Save button. The Export Bookmarks File window will close.
Close the Library window.
Your bookmarks are successfully exported from Firefox, to import them into Opera proceed to the next section.
Importing bookmarks into Opera
Click on the Menu button, selectClick on the Bookmarks menu and then select Manage Bookmarks.... The Bookmarks tab will open.
In the Bookmarks tab, click File and select Import Firefox Bookmarks....
Locate the bookmarks.html file you previously created and then click the Open button. A box will come up informing you that your bookmarks have been imported.