diff --git a/roles/bird2/templates/bird/bird.conf.j2 b/roles/bird2/templates/bird/bird.conf.j2
index 56b2dc10..963503ba 100644
--- a/roles/bird2/templates/bird/bird.conf.j2
+++ b/roles/bird2/templates/bird/bird.conf.j2
@@ -18,6 +18,10 @@ router id {{ bird.id }};
 # Turn on global debugging of all protocols (all messages or just selected classes)
 # debug protocols all;
 
+# To get meaningful uptime information in the Prometheus exporter, BIRD needs to be
+# configured to use ISO-format timestamps
+timeformat protocol iso long;
+
 # +----------------------+
 # | CONSTANT DEFINITIONS |
 # +----------------------+