Meduza’s analysts break down how Russia’s temporary SIM card blocks are supposed to stop drones — and why they won’t
Since November 10, Russia has been running an experiment it calls SIM card “cooling” — temporarily cutting off mobile Internet access for cards that have either connected to foreign networks while roaming or remained offline for more than 72 hours. SIM cards returning from abroad are automatically disconnected for 24 hours, though users can, in theory, restore service sooner by completing a CAPTCHA. Officially, the measure is meant to prevent Ukrainian drones equipped with LTE modems from connecting to Russian mobile networks during attacks. In practice, though, it’s a major inconvenience for travelers, residents of border regions, and even foreign visitors, whose SIM cards are also “cooled.” Whether the system actually improves security in practice, however, is an open question. At first glance, it looks plausible — it’s no coincidence that Ukraine has discussed a similar approach. In reality, though, the benefits are limited, and this new layer of protection is easily bypassed. Meduza explains how drones utilize mobile networks during attacks and whether “cooling” can do anything to stop them.
First, a quick explanation of what this new “cooling” mechanism actually is.
Russia’s Digital Development Ministry has begun testing a new policy in which mobile operators are required to block Internet access for SIM cards that have recently connected to foreign networks while roaming, as well as for cards that have been inactive for more than 72 hours.
During the blocking period, users can still access websites on government-approved “whitelists” — including the state services portal Gosuslugi, Russian social networks, and search engines.
A user can lift the block by completing a CAPTCHA through a link sent by their mobile carrier. For now, the system doesn’t work with all operators, and, naturally, the CAPTCHA method isn’t available on devices that lack a compatible interface. The goal of the measure is to completely prevent SIM cards installed in Ukrainian drones from connecting to Russian mobile networks.
Other restrictions serve the same purpose, and some of them are even more disruptive for civilians. These range from a ban on transferring SIM cards to other people to indefinite shutdowns of mobile Internet in certain areas. It’s clear that if “cooling” were the only — yet effective — way to counter drones, it would be a far better alternative to a full-scale shutdown.
So how do Ukrainian drones actually connect to Russian mobile networks?
First, it’s important to note that most military drones flying over Ukraine, Russia, and the front line between the two armies don’t use mobile communication at all.
Almost all drones on the battlefield are controlled directly by operators via two-way radio or, in some cases, fiber-optic cable. Still, in recent months, drones equipped with LTE modems have begun appearing more frequently in the rear areas of both armies — mostly over Ukrainian territory.
Long-range drones used for strikes deep inside Ukraine and Russia typically rely on a standard navigation suite that includes an inertial system — which isn’t vulnerable to electronic warfare but gradually accumulates internal errors — and a satellite navigation system that helps correct those errors. The latter, however, is highly susceptible to interference: the weak signals from navigation satellites can be jammed or replaced with fake ones. The goal of such electronic countermeasures is to reduce the precision of enemy drones, missiles, and guided bombs to the point that they can no longer effectively hit their targets.
The main defense against jamming and “spoofing” — that is, falsified signals — lies in increasing the complexity of the receiver antenna. Russian Shahed/Geran drones, for instance, are equipped with complex navigation systems featuring more than 10 satellite-signal receivers. The data from these receivers are processed by an onboard computer capable of comparing and filtering out false signals.
Both sides routinely complain that the accuracy of their drones, missiles, and bombs — including Western-made ones — can suddenly drop in certain areas because of enemy interference. But those problems are often resolved through relatively simple hardware and software updates.
In theory, connecting to mobile networks could help overcome these issues, since civilian devices like smartphones often rely on cell tower signals for navigation. But mobile networks — unlike satellites — can be switched off entirely, making them unreliable in combat. For that reason, both sides use mobile connectivity only as a supplementary tool, and most long-range drones operate without it altogether.
Still, both sides note that long-range drones that have crashed without detonating do in fact contain mobile communication modems — though such findings are reported mainly by Ukrainian experts, since similar evidence on the Russian side is likely concealed by military censorship. These modems often contain Russian, Ukrainian, or even foreign SIM cards.
The main purpose of these modems is to transmit telemetry data from the drone back to command. In theory, this feedback could help planners refine future strikes, avoiding areas with heavy satellite jamming or air-defense systems. All of these zones lie far beyond the range of standard radio communication.
In some cases, both sides also use mobile modems to transmit video from onboard cameras. But this too has its problems: the signal suffers from significant lag, making it nearly useless for hitting moving targets. The only viable option is striking relatively stationary but important targets that move occasionally — for example, military aircraft parked at airfields but capable of taxiing between spots. For the most part, though, long-range drones continue to strike fixed targets with known coordinates, where real-time video isn’t needed.
More often, camera-equipped drones — at least on the Russian side — are used for strikes and surveillance in the near rear. Shahed/Geran drones, for example, have repeatedly attacked railway infrastructure, including trains at front-line stations. Such strikes clearly required real-time target identification. Fixed-wing drones used for attacks on armored vehicles and other key targets in the rear also sometimes carry mobile modems. It remains unclear, however, how effective freezing SIM cards that have recently connected to roaming networks could be against them.
Finally, LTE modems with SIM cards can play a role in high-profile — and militarily painful — special operations. In June 2025, Ukrainian intelligence used small kamikaze drones equipped with mobile communication to attack Russian long-range and strategic aircraft at Air Force bases deep inside the country. The drones were piloted by operators located thousands of kilometers away, inside Ukraine. The communication lag was overcome with the help of ArduPilot, an open-source UAV autopilot system.
Russian security services fear another strike of this kind — and it’s likely that all relevant agencies, including the Digital Development Ministry, have been ordered to devise countermeasures. Still, it’s not hard to see that the SIM “cooling” system won’t solve the problem. Ukrainian operatives could simply purchase dozens of Russian SIM cards and “unfreeze” them according to the official reactivation rules.
Ukrainian experts claim their military has learned to block SIM cards on enemy drones “in flight.” The exact mechanism and effectiveness of such technology remain unclear, but it may work by targeting SIM cards that move between cell towers at speeds of several hundred kilometers per hour.
So does that mean the SIM card ‘cooling’ system won’t help stop drone attacks?
That’s what it looks like. The new measures may complicate the planning of certain operations, but they won’t be enough to halt Ukrainian drone strikes deep inside Russia.
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Meduza’s Razbor (“Explainers”) team