diff --git src/bp-activity/classes/class-bp-activity-component.php src/bp-activity/classes/class-bp-activity-component.php
index d44879fd3..5d65f693f 100644
--- src/bp-activity/classes/class-bp-activity-component.php
+++ src/bp-activity/classes/class-bp-activity-component.php
@@ -331,9 +331,16 @@ class BP_Activity_Component extends BP_Component {
 
 		// Menus for logged in user.
 		if ( is_user_logged_in() ) {
+			// Get the base item (Activty Member's primary nav item).
+			$base_item = buddypress()->members->nav->get( bp_get_activity_slug() );
 
-			// Setup the logged in user variables.
-			$activity_link = trailingslashit( bp_loggedin_user_domain() . bp_get_activity_slug() );
+			if ( isset( $base_item->link, $base_item->default_subnav_slug ) ) {
+				$activity_link  = $base_item->link;
+				$default_subnav = $base_item->default_subnav_slug;
+			} else {
+				$activity_link  = trailingslashit( bp_loggedin_user_domain() . bp_get_activity_slug() );
+				$default_subnav = 'just-me';
+			}
 
 			// Unread message count.
 			if ( bp_activity_do_mentions() ) {
@@ -362,7 +369,7 @@ class BP_Activity_Component extends BP_Component {
 				'parent'   => 'my-account-' . $this->id,
 				'id'       => 'my-account-' . $this->id . '-personal',
 				'title'    => _x( 'Personal', 'My Account Activity sub nav', 'buddypress' ),
-				'href'     => $activity_link,
+				'href'     => $default_subnav === 'just-me' ? $activity_link : trailingslashit( $activity_link . 'just-me' ),
 				'position' => 10
 			);
 
@@ -372,7 +379,7 @@ class BP_Activity_Component extends BP_Component {
 					'parent'   => 'my-account-' . $this->id,
 					'id'       => 'my-account-' . $this->id . '-mentions',
 					'title'    => $title,
-					'href'     => trailingslashit( $activity_link . 'mentions' ),
+					'href'     => $default_subnav === 'mentions' ? $activity_link : trailingslashit( $activity_link . 'mentions' ),
 					'position' => 20
 				);
 			}
@@ -383,7 +390,7 @@ class BP_Activity_Component extends BP_Component {
 					'parent'   => 'my-account-' . $this->id,
 					'id'       => 'my-account-' . $this->id . '-favorites',
 					'title'    => _x( 'Favorites', 'My Account Activity sub nav', 'buddypress' ),
-					'href'     => trailingslashit( $activity_link . 'favorites' ),
+					'href'     => $default_subnav === 'favorites' ? $activity_link : trailingslashit( $activity_link . 'favorites' ),
 					'position' => 30
 				);
 			}
@@ -394,7 +401,7 @@ class BP_Activity_Component extends BP_Component {
 					'parent'   => 'my-account-' . $this->id,
 					'id'       => 'my-account-' . $this->id . '-friends',
 					'title'    => _x( 'Friends', 'My Account Activity sub nav', 'buddypress' ),
-					'href'     => trailingslashit( $activity_link . bp_get_friends_slug() ),
+					'href'     => $default_subnav === bp_get_friends_slug() ? $activity_link : trailingslashit( $activity_link . bp_get_friends_slug() ),
 					'position' => 40
 				);
 			}
@@ -405,7 +412,7 @@ class BP_Activity_Component extends BP_Component {
 					'parent'   => 'my-account-' . $this->id,
 					'id'       => 'my-account-' . $this->id . '-groups',
 					'title'    => _x( 'Groups', 'My Account Activity sub nav', 'buddypress' ),
-					'href'     => trailingslashit( $activity_link . bp_get_groups_slug() ),
+					'href'     => $default_subnav === bp_get_groups_slug() ? $activity_link : trailingslashit( $activity_link . bp_get_groups_slug() ),
 					'position' => 50
 				);
 			}
diff --git src/bp-core/bp-core-buddybar.php src/bp-core/bp-core-buddybar.php
index afbb2f287..1df6bae39 100644
--- src/bp-core/bp-core-buddybar.php
+++ src/bp-core/bp-core-buddybar.php
@@ -325,18 +325,41 @@ function bp_core_new_nav_default( $args = '' ) {
 
 	$parent_nav = reset( $parent_nav );
 
-	if ( ! empty( $parent_nav->screen_function ) ) {
-		// Remove our screen hook if screen function is callable.
-		if ( is_callable( $parent_nav->screen_function ) ) {
-			remove_action( 'bp_screens', $parent_nav->screen_function, 3 );
-		}
-	}
-
 	// Edit the screen function for the parent nav.
-	$bp->members->nav->edit_nav( array(
-		'screen_function'     => &$r['screen_function'],
-		'default_subnav_slug' => $r['subnav_slug'],
-	), $parent_nav->slug );
+	$bp->members->nav->edit_nav(
+		array(
+			'screen_function'     => &$r['screen_function'],
+			'default_subnav_slug' => $r['subnav_slug'],
+		),
+		$parent_nav->slug
+	);
+
+	/**
+	 * Update secondary nav items:
+	 * - The previous default nav item needs have its slug added to its link property.
+	 * - The new default nav item needs to have its slug removed from its link property.
+	 */
+	$previous_default_subnav = $bp->members->nav->get( $parent_nav->slug . '/' . $parent_nav->default_subnav_slug );
+
+	// Edit the link of the previous default nav item.
+	$bp->members->nav->edit_nav(
+		array(
+			'link' => trailingslashit( $previous_default_subnav->link . $previous_default_subnav->slug ),
+		),
+		$previous_default_subnav->slug,
+		$parent_nav->slug
+	);
+
+	$new_default_subnav = $bp->members->nav->get( $parent_nav->slug . '/' . $r['subnav_slug'] );
+
+	// Edit the link of the new default nav item.
+	$bp->members->nav->edit_nav(
+		array(
+			'link' => rtrim( untrailingslashit( $new_default_subnav->link ), $new_default_subnav->slug ),
+		),
+		$new_default_subnav->slug,
+		$parent_nav->slug
+	);
 
 	if ( bp_is_current_component( $parent_nav->slug ) ) {