Optus VPN Throttling Australia — Why It Happens and How to Fix It (2026)

Some Optus customers notice their VPN slows down significantly — not because the VPN itself is slow, but because Optus is throttling it. Here's what's actually happening and how to sort it.

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Does Optus throttle VPN traffic?

Yes, on certain plans. Optus applies traffic management policies that can slow detected VPN connections, particularly during peak hours (roughly 6–11pm on weeknights).

The mechanism is deep packet inspection (DPI) — a technology that lets Optus identify encrypted VPN traffic by its traffic patterns, even if it can't read the contents. Once identified, Optus can apply lower throughput limits to that traffic class.

This isn't unique to Optus — it's common practice among Australian ISPs, and Telstra does the same thing on certain plans. But Optus is particularly known for it on budget NBN plans and on the Optus mobile network.

Signs your Optus VPN is being throttled:

• VPN runs fine until around 7–9pm, then drops significantly
• Speed tests without the VPN are normal; speed tests with the VPN are much slower
• Disconnecting and reconnecting doesn't fix it
• Switching to a closer server doesn't help much
• Problem gets worse over consecutive evenings

The pattern of peak-hour slowdowns (rather than constant slowdowns) is the clearest indicator of throttling vs a general VPN performance issue.

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Why Optus throttles VPNs

Optus manages network congestion by prioritising certain types of traffic. VPN traffic — particularly encrypted tunnels — is treated as a lower priority on congested network segments, because Optus can't inspect what's inside it.

This is partly a technical measure (encrypted traffic can't be optimised the same way as, say, video streaming) and partly a commercial one (VPNs bypass some of the traffic monitoring that Optus uses internally).

Which Optus customers are most affected:

• Optus budget NBN plans (Everyday, Basics)
• Optus mobile broadband (home wireless)
• MVNOs that run on the Optus network: Amaysim, Coles Mobile, Woolworths Mobile, Spintel, Dodo Mobile, Southern Phone

Optus's premium NBN plans (Fast Plus, Superfast) tend to see less throttling, though it's not guaranteed.

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How to stop Optus from throttling your VPN

The fix is obfuscation — a VPN mode that disguises encrypted VPN traffic so it looks like ordinary HTTPS web traffic. Optus's DPI can't distinguish it from normal browsing, so it doesn't get throttled.

Two VPNs handle this well from Australian testing:

NordVPN — obfuscated servers

NordVPN's obfuscated servers wrap your VPN connection in standard HTTPS-like traffic. To enable them:

1. Open NordVPN → Settings → Connection
2. Set protocol to OpenVPN TCP
3. Toggle on Obfuscated servers
4. Connect — NordVPN will automatically route through an obfuscated server

In testing from Sydney on Optus NBN, switching to obfuscated servers recovered roughly 85–90% of normal speeds during peak hours. The overhead from obfuscation is about 10–15% compared to a standard NordVPN connection, but that's still dramatically better than being throttled to 20–30% of normal.

For a full breakdown of NordVPN's Australian performance, see our NordVPN review for Australian users.

Get NordVPN — includes obfuscated servers

Editor's Choice · Fastest speeds in Australia

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Surfshark — Camouflage mode

Surfshark's Camouflage mode activates automatically when you use the OpenVPN protocol (either TCP or UDP). You don't need to manually enable it — switching protocols is enough.

To use Camouflage mode on Surfshark:

1. Open Surfshark → Settings → VPN Settings → Protocol
2. Select OpenVPN (TCP) — Camouflage mode activates automatically
3. Connect as normal

Surfshark's Camouflage mode performed slightly behind NordVPN's obfuscated servers in Australian peak-hour testing, but the difference was minor. If you're already a Surfshark subscriber, it works well. For pricing and full test results, see our Surfshark review for Australians.

Get Surfshark — includes Camouflage mode

Unlimited devices · From AUD $3.49/mo

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ISP speed context: Optus NBN performance

For reference, here's what you can reasonably expect on an unthrottled Optus NBN 100 plan with each VPN connected to Sydney servers:

| VPN | Protocol | Avg download speed (Sydney server) | Notes | |---|---|---|---| | NordVPN | NordLynx (standard) | ~85 Mbps | Best option when not throttled | | NordVPN | OpenVPN TCP + Obfuscated | ~72 Mbps | Use when throttled — much better than unobfuscated under throttle | | Surfshark | WireGuard (standard) | ~78 Mbps | Good unthrottled | | Surfshark | OpenVPN + Camouflage | ~65 Mbps | Use when throttled | | No VPN (baseline) | — | ~95 Mbps | Optus NBN 100 typical |

Results from NBN 100 Optus residential connection, evening testing. Speeds vary by server load and your local loop quality.

When throttled, standard VPN connections on Optus can drop to 15–30 Mbps during peak hours. Obfuscation typically brings this back to 60–75 Mbps — a significant improvement.

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VPN features that don't help with Optus throttling

A few things that won't fix Optus throttling, despite being commonly suggested:

Switching servers: Doesn't help, because the throttling happens at your Optus connection point before the traffic reaches the VPN server. The destination doesn't matter.

Using a faster VPN: Same issue — if Optus is throttling encrypted traffic, a faster VPN just gets throttled to the same cap.

Using TCP vs UDP (without obfuscation): Changing protocols without enabling obfuscation doesn't hide the VPN traffic signature. Optus can still detect and throttle it.

Restarting the VPN: Throttling policies apply at the network level, not the session level. Reconnecting won't get you better speeds.

What does help:

• Obfuscation (covered above)
• Connecting to a VPN at a different time of day (throttling is often peak-hours only)
• Upgrading your Optus plan (premium plans tend to have more relaxed traffic management)

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What about Optus Mobile?

Optus mobile (4G and 5G) also applies traffic shaping, and VPN traffic can be throttled on their mobile network — particularly when the network is congested.

The same obfuscation fix applies. On mobile, you'll typically use the same VPN app with obfuscation enabled, and it works the same way.

Optus-network MVNOs to watch:

• Amaysim (Optus network)
• Coles Mobile (Optus network)
• Woolworths Mobile (Optus network)
• Spintel (Optus network)
• Southern Phone (Optus network)

If you're on any of these and experiencing VPN throttling, you're on the same Optus infrastructure. The same obfuscation fixes apply.

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Which VPN to use if you're on Optus

For Optus customers specifically, the key features to look for in a VPN:

1. Obfuscation support — not all VPNs have this
2. Australian server coverage — more Sydney/Melbourne servers = less congestion at peak
3. No-logs policy — independently audited

Both NordVPN and Surfshark tick all three boxes. For a detailed comparison of both on Australian ISPs, see our NordVPN vs Surfshark head-to-head.

If you want to see how all the major VPNs compare for Australian users generally, our best VPN Australia comparison covers speed testing from Sydney and Melbourne.

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For the full picture on ISP throttling in Australia — including Telstra and how the two compare — see our guide to Optus and Telstra VPN throttling.

Tested May 2026 on Optus NBN 100 in Sydney. Results vary by plan, location, and time of day.