diff --git a/cmd/ingestor/db.go b/cmd/ingestor/db.go
index 93d3dc53..d3a3a29a 100644
--- a/cmd/ingestor/db.go
+++ b/cmd/ingestor/db.go
@@ -116,7 +116,8 @@ func applySchema(db *sql.DB) error {
 			battery_mv INTEGER,
 			uptime_secs INTEGER,
 			noise_floor REAL,
-			inactive INTEGER DEFAULT 0
+			inactive INTEGER DEFAULT 0,
+			last_packet_at TEXT DEFAULT NULL
 		);
 
 		CREATE INDEX IF NOT EXISTS idx_nodes_last_seen ON nodes(last_seen);
@@ -421,6 +422,21 @@ func applySchema(db *sql.DB) error {
 		log.Println("[migration] observations.raw_hex column added")
 	}
 
+	// Migration: add last_packet_at column to observers (#last-packet-at)
+	row = db.QueryRow("SELECT 1 FROM _migrations WHERE name = 'observers_last_packet_at_v1'")
+	if row.Scan(&migDone) != nil {
+		log.Println("[migration] Adding last_packet_at column to observers...")
+		db.Exec(`ALTER TABLE observers ADD COLUMN last_packet_at TEXT DEFAULT NULL`)
+		// Backfill: set last_packet_at = last_seen only for observers that have received packets
+		res, err := db.Exec(`UPDATE observers SET last_packet_at = last_seen WHERE packet_count > 0`)
+		if err == nil {
+			n, _ := res.RowsAffected()
+			log.Printf("[migration] Backfilled last_packet_at for %d observers with packets", n)
+		}
+		db.Exec(`INSERT INTO _migrations (name) VALUES ('observers_last_packet_at_v1')`)
+		log.Println("[migration] observers.last_packet_at column added")
+	}
+
 	return nil
 }
 
@@ -504,7 +520,7 @@ func (s *Store) prepareStatements() error {
 		return err
 	}
 
-	s.stmtUpdateObserverLastSeen, err = s.db.Prepare("UPDATE observers SET last_seen = ? WHERE rowid = ?")
+	s.stmtUpdateObserverLastSeen, err = s.db.Prepare("UPDATE observers SET last_seen = ?, last_packet_at = ? WHERE rowid = ?")
 	if err != nil {
 		return err
 	}
@@ -583,9 +599,9 @@ func (s *Store) InsertTransmission(data *PacketData) (bool, error) {
 		err := s.stmtGetObserverRowid.QueryRow(data.ObserverID).Scan(&rowid)
 		if err == nil {
 			observerIdx = &rowid
-			// Update observer last_seen on every packet to prevent
+			// Update observer last_seen and last_packet_at on every packet to prevent
 			// low-traffic observers from appearing offline (#463)
-			_, _ = s.stmtUpdateObserverLastSeen.Exec(now, rowid)
+			_, _ = s.stmtUpdateObserverLastSeen.Exec(now, now, rowid)
 		}
 	}
 
diff --git a/cmd/server/db.go b/cmd/server/db.go
index 46e9590c..d970741c 100644
--- a/cmd/server/db.go
+++ b/cmd/server/db.go
@@ -170,6 +170,7 @@ type Observer struct {
 	BatteryMv     *int     `json:"battery_mv"`
 	UptimeSecs    *int64   `json:"uptime_secs"`
 	NoiseFloor    *float64 `json:"noise_floor"`
+	LastPacketAt  *string  `json:"last_packet_at"`
 }
 
 // Transmission represents a row from the transmissions table.
@@ -972,7 +973,7 @@ func (db *DB) getObservationsForTransmissions(txIDs []int) map[int][]map[string]
 
 // GetObservers returns active observers (not soft-deleted) sorted by last_seen DESC.
 func (db *DB) GetObservers() ([]Observer, error) {
-	rows, err := db.conn.Query("SELECT id, name, iata, last_seen, first_seen, packet_count, model, firmware, client_version, radio, battery_mv, uptime_secs, noise_floor FROM observers WHERE inactive IS NULL OR inactive = 0 ORDER BY last_seen DESC")
+	rows, err := db.conn.Query("SELECT id, name, iata, last_seen, first_seen, packet_count, model, firmware, client_version, radio, battery_mv, uptime_secs, noise_floor, last_packet_at FROM observers WHERE inactive IS NULL OR inactive = 0 ORDER BY last_seen DESC")
 	if err != nil {
 		return nil, err
 	}
@@ -983,7 +984,7 @@ func (db *DB) GetObservers() ([]Observer, error) {
 		var o Observer
 		var batteryMv, uptimeSecs sql.NullInt64
 		var noiseFloor sql.NullFloat64
-		if err := rows.Scan(&o.ID, &o.Name, &o.IATA, &o.LastSeen, &o.FirstSeen, &o.PacketCount, &o.Model, &o.Firmware, &o.ClientVersion, &o.Radio, &batteryMv, &uptimeSecs, &noiseFloor); err != nil {
+		if err := rows.Scan(&o.ID, &o.Name, &o.IATA, &o.LastSeen, &o.FirstSeen, &o.PacketCount, &o.Model, &o.Firmware, &o.ClientVersion, &o.Radio, &batteryMv, &uptimeSecs, &noiseFloor, &o.LastPacketAt); err != nil {
 			continue
 		}
 		if batteryMv.Valid {
@@ -1006,8 +1007,8 @@ func (db *DB) GetObserverByID(id string) (*Observer, error) {
 	var o Observer
 	var batteryMv, uptimeSecs sql.NullInt64
 	var noiseFloor sql.NullFloat64
-	err := db.conn.QueryRow("SELECT id, name, iata, last_seen, first_seen, packet_count, model, firmware, client_version, radio, battery_mv, uptime_secs, noise_floor FROM observers WHERE id = ?", id).
-		Scan(&o.ID, &o.Name, &o.IATA, &o.LastSeen, &o.FirstSeen, &o.PacketCount, &o.Model, &o.Firmware, &o.ClientVersion, &o.Radio, &batteryMv, &uptimeSecs, &noiseFloor)
+	err := db.conn.QueryRow("SELECT id, name, iata, last_seen, first_seen, packet_count, model, firmware, client_version, radio, battery_mv, uptime_secs, noise_floor, last_packet_at FROM observers WHERE id = ?", id).
+		Scan(&o.ID, &o.Name, &o.IATA, &o.LastSeen, &o.FirstSeen, &o.PacketCount, &o.Model, &o.Firmware, &o.ClientVersion, &o.Radio, &batteryMv, &uptimeSecs, &noiseFloor, &o.LastPacketAt)
 	if err != nil {
 		return nil, err
 	}