diff --git a/source/blender/editors/armature/pose_select.cc b/source/blender/editors/armature/pose_select.cc
index 284f9e12272..f6ed35907a8 100644
--- a/source/blender/editors/armature/pose_select.cc
+++ b/source/blender/editors/armature/pose_select.cc
@@ -1139,7 +1139,10 @@ static wmOperatorStatus pose_select_mirror_exec(bContext *C, wmOperator *op)
     /* Remember the pre-mirroring selection flags of the bones. */
     blender::Map<bPoseChannel *, eBone_Flag> old_selection_flags;
     LISTBASE_FOREACH (bPoseChannel *, pchan, &ob->pose->chanbase) {
-      old_selection_flags.add_new(pchan, eBone_Flag(pchan->bone->flag));
+      /* Treat invisible bones as deselected. */
+      const int flags = PBONE_VISIBLE(arm, pchan->bone) ? pchan->bone->flag : 0;
+
+      old_selection_flags.add_new(pchan, eBone_Flag(flags));
     }
 
     LISTBASE_FOREACH (bPoseChannel *, pchan, &ob->pose->chanbase) {
@@ -1148,8 +1151,10 @@ static wmOperatorStatus pose_select_mirror_exec(bContext *C, wmOperator *op)
       }
 
       bPoseChannel *pchan_mirror = BKE_pose_channel_get_mirrored(ob->pose, pchan->name);
-      if (!pchan_mirror || !PBONE_VISIBLE(arm, pchan_mirror->bone)) {
-        set_bone_selection_flags(pchan, eBone_Flag(0));
+      if (!pchan_mirror) {
+        /* If a bone cannot be mirrored, keep its flags as-is. This makes it possible to select
+         * the spine and an arm, and still flip the selection to the other arm (without losing
+         * the selection on the spine). */
         continue;
       }
 
@@ -1157,7 +1162,7 @@ static wmOperatorStatus pose_select_mirror_exec(bContext *C, wmOperator *op)
         pchan_mirror_act = pchan_mirror;
       }
 
-      /* Skip all but the active or its mirror. */
+      /* If active-only, don't touch unrelated bones. */
       if (active_only && !ELEM(arm->act_bone, pchan->bone, pchan_mirror->bone)) {
         continue;
       }