Slow internet is a symptom, not a diagnosis. In South Africa it usually traces back to one of six things — and they need completely different fixes. Moving your router won’t help if the problem is an undersea cable, and upgrading your package won’t help if the problem is that your router is in a cupboard. Work through these in order and you’ll know which one you have.
Start with an actual measurement
Before changing anything, get a number. "It feels slow" is not something you can act on, and it's definitely not something an ISP will act on. Run a speed test and write down the download, upload, ping and jitter.
Then compare it to what you actually pay for. If you're on a 100 Mbps line and seeing 90, your line is fine and the problem is somewhere else — a specific device, a specific site, or Wi-Fi. If you're seeing 12, something is genuinely wrong. Not sure whether your speed is even appropriate for your household? Our speed calculator works out what you actually need, which is often less than people are sold.
One test proves nothing. Speeds vary by the minute. If you're building a case for your ISP, leave our speed monitor running for a day or two — it logs results over time and exports a CSV, which is far harder to wave away than a single screenshot.
Is it your Wi-Fi, or is it the line?
This is the single most useful distinction, and most people skip it. Your fibre line and your Wi-Fi are separate things: the line can be delivering a perfect 200 Mbps to the box on your wall while the far bedroom gets 8 Mbps. That's not a fibre problem, and no ISP can fix it for you.
Test it directly: run a speed test standing next to the router, then run the same test where the problem is. Our Wi-Fi or line? tool does both and tells you which one is at fault. A big drop between the two points at Wi-Fi coverage — which is fixable for free, usually by moving the router. Our guide to fixing slow Wi-Fi covers placement, bands and interference.
Only slow in the evening?
If it's fine at 10am and unusable at 8pm, that's congestion, not a fault. Everyone in your suburb streams at the same time, and somewhere upstream — your ISP's capacity, or the network's — there isn't quite enough to go around at peak.
This is one of the few genuine differences between ISPs selling the identical physical line. Two providers on the same Openserve or Vumatel connection can feel very different at 8pm depending on how much international capacity they buy per customer. It's also the hardest thing to research before signing, which is why customer reviews are worth reading — we rank ISPs by aggregated review score in our best ISP guide.
Only slow on overseas sites?
If local sites fly but anything hosted abroad crawls, the bottleneck is international transit, not your line. South Africa reaches the rest of the internet through a handful of undersea cables, and when one is damaged — which happens more often than most people realise — traffic reroutes the long way around. Latency climbs, throughput drops, and there is nothing you or your ISP can do except wait for the repair ship.
You can spot this pattern: a latency test showing normal local ping but poor performance to overseas services, while your raw download speed on a local server looks fine. Worth knowing so you don't spend a Saturday rearranging furniture over something happening in the Atlantic.
The load-shedding factor
Your fibre line itself doesn't need municipal power — but almost everything around it does. Your router and ONT need a plug. So do the network cabinets in your street and the equipment in your ISP's exchange. Most operators run batteries on critical kit, but batteries degrade, and repeated deep cycles mean some cabinets simply don't come back until they've recharged.
The tell is timing: if outages line up with a schedule rather than appearing at random, you've found your answer. Our uptime monitor timestamps every dropout, which makes the pattern obvious — and gives you something concrete if you do end up logging a fault.
When it really is your ISP
Sometimes you've ruled everything else out and the line is simply not delivering. Consistently well below your package speed, tested by cable, at different times of day, over several days — that's a fault or a provisioning problem, and it's worth logging formally.
- Test over a cable, not Wi-Fi — otherwise the first thing they'll do is blame your Wi-Fi, and they'll be right to.
- Collect several results across different days and times — a CSV from the speed monitor does this for you.
- Log a reference number and note the date you reported it.
- Escalate to ICASA if it isn't resolved — South Africa's communications regulator handles complaints once the provider's own process has failed.
- Check you're not on a throttled product — some "uncapped" packages still shape heavy usage after a threshold.
And if the answer turns out to be that your line is fine but too slow for your household, or your ISP is charging above the going rate for it, that's a different fix. Our am I overpaying? tool compares your price to the cheapest at the same speed.
Worked through all six and still stuck with a line that can't keep up? Check what else reaches your address — there may be a faster network in your street that nobody told you about. Run your address here.