Why Is My NBN Slow? 10 Common Causes & Fixes

Few things are more frustrating than dealing with slow internet when you’re trying to stream your favourite show, join a work meeting, or play games online. If you’ve been wondering, “why is my nbn® slow?”, you’re not alone.

nbn®  can be slow for several reasons, including network congestion, Wi-Fi issues, outdated hardware, or your current plan. The good news is that most nbn®  speed issues are fixable with a few practical checks and changes.

Whether your nbn® is running slow during peak hours or your Wi-Fi keeps dropping out in certain rooms, understanding the cause is the first step to improving your connection. If you’re comparing home nbn® plans, it’s also worth checking whether your current plan still matches your household’s internet usage.

ACCC explains that broadband speeds can vary depending on factors such as network demand, technology type, and in-home setup.

One of the most common reasons for slow nbn® speed is network congestion during peak evening hours.

This usually happens when more people are online streaming, gaming, scrolling, browsing, and joining video calls. During these busy periods, available bandwidth is shared across more users, which can reduce speeds.

The ACCC’s Measuring Broadband Australia reports regularly monitor broadband performance during busy hours, including how services perform in peak periods.

To fix this, you may need to upgrade your plan, switch to a higher speed tier, or reduce heavy internet activity during the busiest times. If your household regularly struggles at night, comparing speed options can help.

Learn More in our Gude: What nbn® Speed Tiers Mean (nbn® 25, 50, 100, 250, 1000)

Sometimes the problem isn’t your connection itself. It may be that your current plan no longer suits how your household uses the internet.

A basic plan may be fine for one person to check emails and browse. But if several people are streaming in 4K, gaming online, working from home and joining video calls, your internet can quickly feel overloaded.

Signs your plan may be too slow include buffering while streaming, frozen video calls, slow downloads, lag while gaming, and slower speeds when multiple people are online.

Upgrading to one of the newer or faster nbn® plans may improve performance, especially for larger households or heavier users.

For businesses or users with higher connectivity demands, business fibre plans may also be worth considering. Business Fibre services typically offer faster speeds, stronger reliability, and better support for cloud systems, VoIP calls, large file transfers, and daily operations that rely on stable internet access.

You can also compare plan types here: nbn® Internet Plans: A Comprehensive Guide for Australian Homes

Sometimes your nbn® connection is working properly, but your Wi-Fi signal is causing the issue. 

Wi-Fi interference is common in Australian homes, especially in apartments, larger houses, or homes with thick walls. Distance from the router, furniture, appliances, and nearby networks can all weaken your signal.

This often explains why your internet feels fast near the router but slow in bedrooms, home offices, or upstairs areas.

To improve Wi-Fi performance, move your router to a central location, keep it away from TVs and microwaves, place it off the floor, and avoid hiding it inside cupboards. If your modem is old or struggling to cover your home, upgrading to a newer nbn® modem may help.

Every connected device in your home shares available bandwidth.

That includes smart TVs, mobile phones, tablets, laptops, gaming consoles, security cameras, smart speakers, and other connected devices. If multiple people are online at the same time, your nbn® may start running slow.

For example, one person might be watching Netflix in 4K, another might be gaming online, and someone else might be on a Zoom call. Add automatic updates or cloud backups into the mix, and your bandwidth usage can quickly spike.

To fix this, disconnect unused devices, pause large downloads, limit simultaneous streaming where possible, or consider upgrading your plan if your household usage has increased.

Old hardware can significantly affect internet performance.

Even if your nbn® plan supports higher speeds, an outdated router may struggle to deliver stable Wi-Fi throughout your home. Older devices may also lack newer Wi-Fi technologies designed for better speed, range, and reliability.

Signs you may need a newer modem to include frequent Wi-Fi dropouts, weak coverage, inconsistent speeds, or poor performance when several devices are connected.

Upgrading to a newer compatible modem may help improve both speed and reliability.

You can also read more here: What Modem Do You Need for nbn®?

Not all nbn® connections perform the same way. Your nbn® technology type can affect the speeds available at your address.

For example, FTTP, or Fibre to the Premises generally offers stronger speed potential because fibre runs directly to the premises. FTTN, or Fibre to the Node, uses fibre to a nearby node and then copper wiring for the final part of the connection, which can affect performance depending on online quality and distance.

nbn® Co explains the different nbn® technology types and how premises may connect to the network.

To fix this, check your property’s nbn® technology type, understand the realistic speed expectations for your address, and ask whether technology upgrades are available in your area. More information on The Complete Guide to nbn® Technology Types (FTTP, FTTN, HFC, FTTC, Fixed Wireless)

Sometimes slow nbn® speed issues are caused by physical installation or cabling problems. 

Damaged cables, poor internal wiring, loose wall socket connections, or incorrect setup can all affect performance. This may be the case if your internet drops often, your speeds fluctuate heavily, or your connection performs poorly even when you are close to the modem.

To troubleshoot, restart your modem, check all cables are secure, test your internet using a wired connection, and contact your provider if issues continue. You can also review How nbn® Installation Works in Australia

Your internet may be slower because of hidden bandwidth usage happening in the background. 

Common culprits include cloud backups, automatic software updates, app syncing, large game downloads, and file uploads. These processes can consume a large amount of bandwidth without you noticing.

To improve nbn® speed, pause updates during busy hours, schedule large downloads overnight, and check which devices are using the most data. This can make a noticeable difference during video calls, gaming sessions, or streaming.

Weather and external issues can occasionally affect internet performance, particularly if there is infrastructure damage, a local outage, or problems with older copper-based connections.

If your NBN suddenly slows after severe weather, check for outages in your area, restart your modem, and contact your provider if the issue does not improve.

If your home internet is supporting a business setup, a standard residential plan may not always be enough.

Heavy usage activities such as frequent video meetings, cloud collaboration, VoIP phone systems, large file transfers, and multiple remote workers can place extra pressure on your connection.

For businesses or heavier users, business nbn® may provide a better fit for reliability and performance.

If you use internet-based calling, you can also read more about VOIP ON THE NBN® – A SIMPLE GUIDE FOR BUSINESSES 

If your NBN is running slow, try these quick fixes first:

1. Restart your modem or router.

2. Move your router to a more central location.

3. Keep your router away from thick walls and appliances.

4. Disconnect unused devices.

5. Pause large downloads or backups

6. Use a wired connection to test your speed

7. Upgrade outdated hardware

8. Compare faster nbn® plans

9. Check for outages in your area

For hardware support, you can also compare modem options here: https://www.yomojo.com.au/nbn/modems

Choosing the right provider can make a real difference when dealing with nbn® speed issues and mobile reliability. Yomojo is trusted by Australians for its flexible plans, competitive pricing and responsive customer support.

Yomojo has an impressive 4.8-star rating on ProductReview.com.au, with customers praising its value, flexibility and easy-to-use service.

Yomojo was also recognised with the 2026 Canstar Outstanding Value Award for Prepaid Mobile Plans, highlighting its strong value and customer-focused approach.

With flexible plans, no lock-in contracts and award-winning value, Yomojo continues to stand out as a trusted Australian telco provider.

Slow internet can be frustrating, but most nbn® speed issues are manageable once you identify the cause.

Whether it’s network congestion, Wi-Fi interference, outdated hardware, background downloads or simply needing a better plan, there are practical steps you can take to improve NBN speed and create a smoother online experience.

If you’re ready to compare nbn® plans, upgrade your setup or explore faster options for your household; Yomojo’s home internet plans are a good place to start.