Website speed on South African mobile networks

Website speed in South Africa depends more on the site than on the network. According to Opensignal's August 2025 report, average mobile download speeds across the five national operators ranged from 17.5 to 60.1 Mbps. That is enough for a well-built page. Heavy pages, distant servers and slower phones are what make a site feel slow, and the gap between the best and worst connection is wide.

What the mobile networks deliver

The figures below come from Opensignal's South Africa Mobile Network Experience report of August 2025, based on data collected from 1 May to 29 July 2025.

• Download speed. Opensignal reported an average Download Speed Experience of 60.1 Mbps on MTN, 42.0 Mbps on Vodacom, 37.1 Mbps on Cell C, 18.3 Mbps on Telkom and 17.5 Mbps on Rain.
• Upload speed. Opensignal's upload figures ranged from 4.8 Mbps on Telkom to 10.1 Mbps on MTN.
• Signal. Opensignal found that users on all five operators had a 3G, 4G or 5G connection more than 98% of the time.
• 5G. Opensignal's 5G Availability figure, the share of time users with 5G devices spent connected to 5G, was 12.4% on MTN and 7.6% on Vodacom.

Three points follow for anyone who runs a website.

1. The fastest operator's average is more than three times the slowest. Your visitors are spread across all of them.
2. Most browsing does not happen on 5G. A site tested only on 5G or office fibre is tested in conditions most visitors do not have.
3. These are averages. A visitor in a weak signal area, on an older phone or at a busy time of day gets less.

How Google measures speed

Google measures page experience with three Core Web Vitals. According to Google's web.dev documentation, a good result is:

• Largest Contentful Paint (loading): 2.5 seconds or less
• Interaction to Next Paint (responsiveness): 200 milliseconds or less
• Cumulative Layout Shift (visual stability): 0.1 or less

Google assesses these at the 75th percentile of page loads, with mobile and desktop measured separately. So the mobile result reflects your slower visits, not your average ones. Google Search's documentation recommends that site owners achieve good Core Web Vitals, and says this matches what its ranking systems seek to reward. It does not say that speed alone decides rankings.

Lab tests and field data

PageSpeed Insights shows two kinds of result, and they often disagree.

• Field data comes from the Chrome User Experience Report. It reflects real visits to your site over the previous 28 days, on the devices and networks your visitors use.
• Lab data comes from Lighthouse, which simulates one page load on a mid-tier phone on a mobile network. Google's documentation says these tests run from data centres in North America, Europe or Asia.

For a South African site, that last point matters. The lab test is not run from South Africa, so it does not show what a local visitor on a local network gets. Where field data exists for your site, it is the better guide. Low-traffic sites may have no field data, and then testing on real phones is the fallback.

Why sites feel slow on mobile

• Page weight. Large images, background video, several font families and sliders all have to be downloaded before the page is usable. On an 18 Mbps connection, every extra megabyte is felt.
• Scripts. Chat widgets, trackers, pop-ups and unused plugins all run on the visitor's phone. Mid-range phones process them more slowly than a new flagship or a laptop.
• Server distance and response time. Every request travels to the server and back. A slow or distant server adds delay before anything appears. PageSpeed Insights treats a server response of 0.8 seconds or less as good.
• No caching. Without caching, the server rebuilds each page for each visitor.
• Layout shift. Images and embeds without reserved space push content around as they load.

A checklist for a faster site

• Size images to the space they fill, and compress them.
• Load images below the first screen only when they are needed.
• Give the main image on each page priority, since it usually sets the Largest Contentful Paint.
• Replace autoplay background video on phones with a still image.
• Limit fonts to the weights the design uses.
• Remove scripts and plugins that no longer earn their place. Delay the rest until the page is usable.
• Turn on page caching, and use a content delivery network where it helps.
• Host close to most of your visitors, on a server that responds quickly. See WordPress hosting in South Africa: local vs international.
• Reserve space for images, embeds and banners so the layout does not jump.
• Keep forms and booking steps light. They are where a slow page costs an enquiry.

How to test your own site

1. Run the page through PageSpeed Insights and read the mobile field data first.
2. Open the Core Web Vitals report in Search Console to see which groups of pages fail.
3. Open the site on a mid-range phone using mobile data, not Wi-Fi. Try more than one network if you can.
4. Test the pages that earn money: the home page, service pages, product pages and the contact or booking page.
5. Fix the largest problem, then test again. Field data takes up to 28 days to reflect a change.

How Stryx approaches speed

Stryx designs sites desktop-down and builds them to rescale to every screen size, with speed and usability on phones checked before launch. Care plan clients choose their hosting region, including South Africa. No one can guarantee a score or a ranking, but the causes of a slow site can be found and fixed.

See speed optimisation and why is my WordPress site slow, or get in touch to have a site looked at.