Step 1 : Hide default login menu for Logged Out members. 


Since we need the login menu for logged in members, we'll only hide it for logged out users.


Simply add this CSS in theme customiser :


  

#headertop .topmenu:first-child {
  display: none;
}
.logged-in #headertop .topmenu:first-child {
  display: block;
}

  



STEP 2 : Add a menu link in the top menu


Go to WP Admin -> Appearance -> Menus

Add the login link from the BuddyPress menu tab.



Video: