diff --git a/simulator/app.py b/simulator/app.py
index f7a639f..45d3f49 100644
--- a/simulator/app.py
+++ b/simulator/app.py
@@ -108,5 +108,19 @@ def restore_rs485():
     return jsonify({"success": True, "rs485_connected": True})
 
 
+@app.route("/comms/latency", methods=["POST"])
+def set_latency():
+    data = request.get_json(force=True)
+    pico.set_latency(data.get("latency_ms", 0))
+    return jsonify({"success": True, "latency_ms": pico.transport.latency_ms})
+
+
+@app.route("/comms/packet-loss", methods=["POST"])
+def set_packet_loss():
+    data = request.get_json(force=True)
+    pico.set_packet_loss(data.get("percent", 0))
+    return jsonify({"success": True, "packet_loss_percent": pico.transport.packet_loss_percent})
+
+
 if __name__ == "__main__":
     app.run(host="0.0.0.0", port=5000, debug=True)
diff --git a/simulator/pico_sim.py b/simulator/pico_sim.py
index 0456889..0b85bd0 100644
--- a/simulator/pico_sim.py
+++ b/simulator/pico_sim.py
@@ -7,30 +7,30 @@ from protocol import (
     toggle_ignition_request,
     toggle_sensor_fault_request,
 )
+from transport import RS485Transport
 
 
 class PicoSimulator:
     def __init__(self, controller):
-        self.controller = controller
+        self.transport = RS485Transport(controller)
         self.last_status = None
         self.primary_link = "rs485"
-        self.rs485_connected = True
         self.backup_link_available = True
         self.messages_sent = 0
         self.messages_received = 0
         self.last_message_time = None
+        self.last_latency_ms = None
 
     def send_message(self, message):
         self.messages_sent += 1
+        start = time.time()
 
-        if not self.rs485_connected:
-            return {
-                "type": "error",
-                "success": False,
-                "error": "RS-485 disconnected"
-            }
+        response = self.transport.send(message)
 
-        response = self.controller.handle_message(message)
+        if response.get("type") == "error":
+            return response
+
+        self.last_latency_ms = round((time.time() - start) * 1000, 1)
         self.messages_received += 1
         self.last_message_time = int(time.time())
         return response
@@ -42,9 +42,7 @@ class PicoSimulator:
             if self.last_status:
                 self.last_status["network"]["rs485_connected"] = False
                 self.last_status["network"]["communication_lost"] = True
-                self.last_status["network"]["messages_sent"] = self.messages_sent
-                self.last_status["network"]["messages_received"] = self.messages_received
-                self.last_status["network"]["last_message_time"] = self.last_message_time
+                self.add_comms_to_status(self.last_status)
                 return self.last_status
 
             return {
@@ -59,22 +57,24 @@ class PicoSimulator:
                     "communication_lost": True,
                     "wifi_enabled": False,
                     "wifi_override_active": False,
-                    "starlink_enabled": False,
-                    "messages_sent": self.messages_sent,
-                    "messages_received": self.messages_received,
-                    "last_message_time": self.last_message_time
+                    "starlink_enabled": False
                 },
                 "config": {}
             }
 
         self.last_status = response["data"]
-        self.last_status["network"]["rs485_connected"] = self.rs485_connected
+        self.last_status["network"]["rs485_connected"] = self.transport.connected
         self.last_status["network"]["communication_lost"] = False
-        self.last_status["network"]["messages_sent"] = self.messages_sent
-        self.last_status["network"]["messages_received"] = self.messages_received
-        self.last_status["network"]["last_message_time"] = self.last_message_time
+        self.add_comms_to_status(self.last_status)
         return self.last_status
 
+    def add_comms_to_status(self, status):
+        status["network"]["messages_sent"] = self.messages_sent
+        status["network"]["messages_received"] = self.messages_received
+        status["network"]["last_message_time"] = self.last_message_time
+        status["network"]["latency_ms"] = self.last_latency_ms
+        status["network"]["packet_loss_percent"] = self.transport.packet_loss_percent
+
     def set_relay(self, relay, state):
         return self.send_message(set_relay_request(relay, state))
 
@@ -88,17 +88,26 @@ class PicoSimulator:
         return self.send_message(toggle_sensor_fault_request(sensor))
 
     def disconnect_rs485(self):
-        self.rs485_connected = False
+        self.transport.disconnect()
 
     def restore_rs485(self):
-        self.rs485_connected = True
+        self.transport.restore()
+
+    def set_latency(self, latency_ms):
+        self.transport.set_latency(latency_ms)
+
+    def set_packet_loss(self, percent):
+        self.transport.set_packet_loss(percent)
 
     def get_comms(self):
         return {
             "primary": self.primary_link,
             "backup_available": self.backup_link_available,
-            "rs485_connected": self.rs485_connected,
+            "rs485_connected": self.transport.connected,
             "messages_sent": self.messages_sent,
             "messages_received": self.messages_received,
-            "last_message_time": self.last_message_time
+            "last_message_time": self.last_message_time,
+            "latency_ms": self.last_latency_ms,
+            "configured_latency_ms": self.transport.latency_ms,
+            "packet_loss_percent": self.transport.packet_loss_percent
         }
diff --git a/simulator/templates/index.html b/simulator/templates/index.html
index 3b96a87..ef41eb9 100644
--- a/simulator/templates/index.html
+++ b/simulator/templates/index.html
@@ -97,11 +97,27 @@
             <div>Messages Sent <strong id="commsSent">--</strong></div>
             <div>Messages Received <strong id="commsReceived">--</strong></div>
             <div>Last Message <strong id="commsLast">--</strong></div>
+            <div>Latency <strong id="commsLatency">--</strong></div>
+            <div>Packet Loss <strong id="commsPacketLoss">--</strong></div>
         </div>
 
         <button onclick="disconnectRs485()">Disconnect RS-485</button>
         <button onclick="restoreRs485()">Restore RS-485</button>
 
+        <div class="settings-list">
+            <label>
+                Simulated Latency ms
+                <input id="latencyInput" type="number" value="0">
+            </label>
+
+            <label>
+                Packet Loss %
+                <input id="packetLossInput" type="number" value="0">
+            </label>
+
+            <button onclick="saveCommsSimulation()">Save Comms Simulation</button>
+        </div>
+
         <h2>Sensor Fault Simulation</h2>
         <div class="settings-list">
             <button onclick="toggleSensorFault('fridge_zone_1')">Toggle Fridge Zone 1 Fault</button>
@@ -389,6 +405,14 @@ async function loadStatus() {
     document.getElementById('commsLast').textContent = data.network.last_message_time
         ? new Date(data.network.last_message_time * 1000).toLocaleTimeString()
         : '--';
+    document.getElementById('commsLatency').textContent =
+        data.network.latency_ms !== null && data.network.latency_ms !== undefined
+            ? `${data.network.latency_ms} ms`
+            : '--';
+    document.getElementById('commsPacketLoss').textContent =
+        data.network.packet_loss_percent !== undefined
+            ? `${data.network.packet_loss_percent}%`
+            : '--';
 
     updateSleepOverlay(data.vehicle?.ignition_on ?? true);
 
@@ -462,6 +486,25 @@ async function restoreRs485() {
     loadStatus();
 }
 
+async function saveCommsSimulation() {
+    const latency = Number(document.getElementById('latencyInput').value);
+    const packetLoss = Number(document.getElementById('packetLossInput').value);
+
+    await fetch('/comms/latency', {
+        method: 'POST',
+        headers: {'Content-Type': 'application/json'},
+        body: JSON.stringify({latency_ms: latency})
+    });
+
+    await fetch('/comms/packet-loss', {
+        method: 'POST',
+        headers: {'Content-Type': 'application/json'},
+        body: JSON.stringify({percent: packetLoss})
+    });
+
+    loadStatus();
+}
+
 async function toggleSensorFault(name) {
     await fetch(`/sensor/${name}/fault`, {
         method: 'POST',
diff --git a/simulator/transport.py b/simulator/transport.py
new file mode 100644
index 0000000..db66024
--- /dev/null
+++ b/simulator/transport.py
@@ -0,0 +1,43 @@
+import random
+import time
+
+
+class RS485Transport:
+    def __init__(self, controller):
+        self.controller = controller
+        self.connected = True
+        self.latency_ms = 0
+        self.packet_loss_percent = 0
+
+    def send(self, message):
+        if not self.connected:
+            return {
+                "type": "error",
+                "success": False,
+                "error": "RS-485 disconnected"
+            }
+
+        if self.latency_ms > 0:
+            time.sleep(self.latency_ms / 1000)
+
+        if self.packet_loss_percent > 0:
+            if random.randint(1, 100) <= self.packet_loss_percent:
+                return {
+                    "type": "error",
+                    "success": False,
+                    "error": "RS-485 packet lost"
+                }
+
+        return self.controller.handle_message(message)
+
+    def disconnect(self):
+        self.connected = False
+
+    def restore(self):
+        self.connected = True
+
+    def set_latency(self, latency_ms):
+        self.latency_ms = max(0, int(latency_ms))
+
+    def set_packet_loss(self, percent):
+        self.packet_loss_percent = max(0, min(100, int(percent)))