diff --git a/lib/spandex.ex b/lib/spandex.ex
index c5f184a..c4de405 100644
--- a/lib/spandex.ex
+++ b/lib/spandex.ex
@@ -453,7 +453,7 @@ defmodule Spandex do
     adapter = opts[:adapter]
 
     with {:ok, top_span} <- span(name, opts, span_context, adapter) do
-      Logger.metadata(trace_id: span_context.trace_id, span_id: top_span.id)
+      Logger.metadata(trace_id: to_string(span_context.trace_id), span_id: to_string(top_span.id))
 
       trace = %Trace{
         id: span_context.trace_id,
@@ -483,7 +483,7 @@ defmodule Spandex do
 
     with {:ok, span} <- Span.child_of(current_span, name, adapter.span_id(), adapter.now(), opts),
          {:ok, _trace} <- strategy.put_trace(opts[:trace_key], %{trace | stack: [span | trace.stack]}) do
-      Logger.metadata(span_id: span.id, trace_id: trace.id)
+      Logger.metadata(span_id: to_string(span.id), trace_id: to_string(trace.id))
       {:ok, span}
     end
   end
@@ -495,7 +495,7 @@ defmodule Spandex do
 
     with {:ok, span} <- span(name, opts, span_context, adapter),
          {:ok, _trace} <- strategy.put_trace(opts[:trace_key], %{trace | stack: [span]}) do
-      Logger.metadata(span_id: span.id, trace_id: trace_id)
+      Logger.metadata(span_id: to_string(span.id), trace_id: to_string(trace_id))
       {:ok, span}
     end
   end
@@ -507,7 +507,7 @@ defmodule Spandex do
     span_context = %SpanContext{trace_id: trace_id}
 
     with {:ok, span} <- span(name, opts, span_context, adapter) do
-      Logger.metadata(trace_id: trace_id, span_id: span.id)
+      Logger.metadata(trace_id: to_string(trace_id), span_id: to_string(span.id))
       trace = %Trace{spans: [], stack: [span], id: trace_id}
       strategy.put_trace(opts[:trace_key], trace)
     end
diff --git a/test/plug/add_context_test.exs b/test/plug/add_context_test.exs
index b92d921..0b681c0 100644
--- a/test/plug/add_context_test.exs
+++ b/test/plug/add_context_test.exs
@@ -50,8 +50,8 @@ defmodule Spandex.Plug.AddContextTest do
 
       assert {:ok, expected_span} = Tracer.start_span("foobar")
 
-      assert Keyword.fetch!(Logger.metadata(), :trace_id) == tid
-      assert Keyword.fetch!(Logger.metadata(), :span_id) == expected_span.id
+      assert Keyword.fetch!(Logger.metadata(), :trace_id) == to_string(tid)
+      assert Keyword.fetch!(Logger.metadata(), :span_id) == to_string(expected_span.id)
 
       {:ok, _} = Tracer.finish_trace()