diff --git a/src/index.mjs b/src/index.mjs
index 7156c51..280a8cf 100644
--- a/src/index.mjs
+++ b/src/index.mjs
@@ -26,8 +26,8 @@ export default async function(indexName, opts = {}) {
     transponder: rec[0],
     callsign: rec[1],
     origin_country: rec[2],
-    time_position: rec[3],
-    last_contact: rec[4],
+    time_position: new Date(rec[3] * 1000),
+    last_contact: new Date(rec[4] * 1000),
     location: rec[5] && rec[6] ? `${rec[6]},${rec[5]}` : null,
     baro_altitude: rec[7],
     geo_altitude: rec[13],