Yes, you can see who logged into your Yahoo account.
Just log in to your Yahoo Mail and click the gear button in the upper right corner.
Choose the Settings menu.
Click the Account Info link so you’ll be brought to your Yahoo account data.
View the Recent Activity on the left panel.
Then you’ll be able to see your Yahoo Mail login or session records as well as extraordinary activity. If you suspect any login that isn’t you, get the IP address and coordinate with law enforcers as well as local internet service providers to identify your hacker.