Java's cities are falling behind their provincial counterparts in Indonesian mobile broadband speeds

Java may be the political, population and economic center of Indonesia, but in mobile broadband speed, Java looks rather provincial, according to Opensignal's analysis of 44 of the largest cities in the country. In fact, to find the fastest download and upload speeds, you have to look to the far corners of Indonesia, to cities where you wouldn't expect to find the most advanced mobile networks.


At the top of our list for Download Speed Experience is West Papua's Kota Sorong, Sulawesi's Kota Gorontalo and the Maluku Islands' Ambon — all of which were statistically tied in this metric with average overall download speeds greater than 11 Mbps. In Upload Speed Experience, Sumatra's Pekanbaru was the uncontested leader with an average speed of 5.9 Mbps.

To find our first Javanese cities in either chart, you have to look well beyond the top 10. Kota Malang and Kota Bandung landed at Nos. 14 and 15 respectively in our Download Speed Experience rankings. In Upload Speed Experience, we have to wend our way down to the No. 18 slot before the first Java population center, Yogyakarta, appears. Indonesia's capital and megalopolis Jakarta rated even lower. Its Download Speed Experience score of 7.8 Mbps was about 4 Mbps lower than the leading cities in our analysis, while its Upload Speed Experience score of 3.5 Mbps was more than 2 Mbps off the leader.

Why does the mobile consumer speed experience improve the further we get away from Java? It's not that Java has weaker or less sophisticated networks — quite the contrary. What we're most likely seeing are dynamics related to competition and demand. Incumbent Telkomsel is already Indonesia's dominant operator, but as we look beyond the major population centers of the country, that dominance only grows. Our latest national report for Indonesia shows that Telkomsel offers the fastest mobile broadband speeds to Opensignal users: its Download Speed Experience score was more than double that of most of its competitors'. In places like Kota Sorong, we see the vast majority of our users accessing Telkomsel networks, therefore the vast majority of mobile consumers are tapping into its faster mobile broadband connections.

Demand also plays a huge role in the typical everyday speeds consumers experience. The more users connect to a network, the more its capacity is spread thin, which can cause average speeds to fall. Though operators tend to concentrate their network and capacity upgrades in the big cities, often those improvements can't keep ahead of the mobile data demands generated by a densely populated, tech-savvy metropolis.

It may seem like we're picking on Java here, but that's because the majority of Indonesia's population lives on that island, thus Java has the highest level of demand. If we extend our analysis to all of Indonesia's largest cities, we see a similar trend. Batam, Bandar Lampung, Makassar and Palembang all fall outside of the top 10 in both our Download and Upload Speed Experience rankings. For every rule there is an exception, though, and in this case that exception is Sumatra's Medan, the largest Indonesian city outside of Java. Medan landed in the top 6 of both our Download and Upload Speed Experience rankings, showing the city is able to maintain relatively fast speeds despite demand and a high level of competition. Perhaps Medan could provide some valuable insights to operators upgrading their networks in Indonesia's largest cities in the future.