diff --git a/base/strings/io.jl b/base/strings/io.jl
index 9204310129729..46353ff6f7c29 100644
--- a/base/strings/io.jl
+++ b/base/strings/io.jl
@@ -354,12 +354,20 @@ function join(io::IO, iterator, delim="")
 end
 
 function _join_preserve_annotations(iterator, args...)
-    if _isannotated(eltype(iterator)) || any(_isannotated, args)
+    if isconcretetype(eltype(iterator)) && !_isannotated(eltype(iterator)) && !any(_isannotated, args)
+        sprint(join, iterator, args...)
+    else
         io = AnnotatedIOBuffer()
         join(io, iterator, args...)
-        read(seekstart(io), AnnotatedString{String})
-    else
-        sprint(join, iterator, args...)
+        # If we know (from compile time information, or dynamically in the case
+        # of iterators with a non-concrete eltype), that the result is annotated
+        # in nature, we extract an `AnnotatedString`, otherwise we just extract
+        # a plain `String` from `io`.
+        if isconcretetype(eltype(iterator)) || !isempty(io.annotations)
+            read(seekstart(io), AnnotatedString{String})
+        else
+            String(take!(io.io))
+        end
     end
 end
 
diff --git a/test/strings/annotated.jl b/test/strings/annotated.jl
index da76f0f020531..8eab0567221e6 100644
--- a/test/strings/annotated.jl
+++ b/test/strings/annotated.jl
@@ -101,6 +101,8 @@ end
                      [(1:4, :label => 5),
                       (5:5, :label => 2),
                       (6:9, :label => 5)])
+    @test join((String(str1), str1), ' ') ==
+        Base.AnnotatedString("test test", [(6:9, :label => 5)])
     @test repeat(str1, 2) == Base.AnnotatedString("testtest", [(1:8, :label => 5)])
     @test repeat(str2, 2) == Base.AnnotatedString("casecase", [(2:3, :label => "oomph"),
                                                        (6:7, :label => "oomph")])