How to find and remove unusual activity on your Yahoo account?
Monitoring your recent login activity can help you discover if unauthorized users have accessed your account. Note that there are legitimate reasons why your history may show unknown locations, such as your mobile device detecting the wrong location or the Internet provider that uses a proxy server.
From a desktop or mobile browser: log in and visit the Recent Activity page.
From most Yahoo mobile applications: -
Note:- If these steps do not work in your application, access the Recent Activity page from your mobile browser.
Depending on how you access your account, there may be up to 3 sections. If you see something you don't recognize, click Log out or Remove next to it, then change your password immediately.