Walk into a phone shop, ask someone to show you their dual-SIM phone, and there is a good chance you will find a familiar combination: Safaricom on SIM 1 and Airtel on SIM 2.
It may look like a simple phone-setting preference, but there are several reasons behind it. Kenya’s mobile market has developed around two particularly strong networks, with Safaricom maintaining the largest share while Airtel has established itself as the country’s second-largest mobile operator.
The latest Communications Authority of Kenya (CA) data shows just how large the market has become. Active mobile subscriptions reached 84.1 million by March 2026, equivalent to a mobile penetration rate of 157.7%. The CA also reported continued growth in mobile data usage and a shift from older 2G and 3G technologies toward 4G and 5G.
So why do many Kenyans keep both networks?
Safaricom Often Becomes the Primary SIM
For many users, Safaricom is more than just a mobile network.
It is connected to a large ecosystem of everyday services, particularly M-PESA.
People use their Safaricom numbers for:
- M-PESA transactions
- Sending and receiving money
- Lipa na M-PESA payments
- PayBill services
- Till payments
- Business transactions
- Bank integrations
- Important personal contacts
- Voice calls and SMS
This makes the Safaricom number particularly valuable as a person’s main telephone line.
The Communications Authority’s data illustrates Safaricom’s continued dominance in mobile communications. During January–March 2026, Safaricom accounted for about 21.0 billion domestic voice minutes, compared with approximately 11.3 billion for Airtel. Safaricom also handled more than 13.1 billion SMS messages during the quarter.
For many users, therefore, putting Safaricom in SIM 1 is simply a way of keeping their most important number as the default line.
M-PESA Makes Safaricom Particularly Important
The relationship between Safaricom and M-PESA is one of the biggest reasons the company has maintained such a strong position in Kenya.
M-PESA is deeply integrated into everyday Kenyan life, from sending money to family members to paying for goods and services.
A person might therefore have an Airtel SIM for internet or calls but still keep their Safaricom number active because it is connected to their M-PESA account and other services.
This creates what economists call a network effect: the more people use a service, the more useful it becomes to other people.
If most of your customers, relatives, friends or business partners use Safaricom, there is a strong reason to keep a Safaricom number even if you also use another network.
Why Airtel Is Often the Second SIM
Airtel has developed a strong position as Kenya’s second major mobile network.
The company competes aggressively on:
- Data bundles
- Voice packages
- Promotions
- Internet offers
- 4G connectivity
- 5G services
- Affordable mobile communication
This makes Airtel attractive as a second network.
Instead of abandoning Safaricom, many users simply add Airtel.
That creates a simple arrangement:
SIM 1: Safaricom
Main number, M-PESA, important calls and everyday transactions.
SIM 2: Airtel
Alternative data, calls, promotions and a backup network.
Dual-SIM Phones Make the Combination Easy
The growth of dual-SIM smartphones has made it unnecessary for consumers to choose only one operator.
A user can have both networks in the same phone and decide which one to use for:
- Mobile data
- Calls
- SMS
- International roaming
- Different promotions
Kenya had 78.7 million mobile phones connected to networks by March 2026, according to the CA. Smartphone adoption is also continuing to increase.
That makes having two SIM cards increasingly convenient.
People Can Compare Prices
Another major reason for having two networks is competition.
Mobile users do not necessarily want to purchase every service from the same operator.
If Safaricom has a better offer for one service, the user can use Safaricom.
If Airtel has a more attractive data or voice promotion, the user can use Airtel.
This gives consumers greater flexibility.
Instead of asking:
“Which network should I choose?”
many Kenyans effectively ask:
“Why choose only one?”
Airtel Can Provide a Backup
There are situations where having a second network is useful simply because mobile coverage and network performance can vary by location.
Someone travelling from Nairobi to another part of Kenya may find that one network performs better in a particular location.
Having two active SIM cards means the user has another option.
This is particularly useful for people who depend on mobile internet for:
- Work
- Online classes
- Mobile banking
- Social media
- YouTube
- Online businesses
- Navigation
- Communication
A second SIM can therefore function as a connectivity backup.
Mobile Internet Is Becoming More Important
The rise of mobile internet is also changing how Kenyans use SIM cards.
The CA reported that mobile broadband consumption reached approximately 800 million GB in January–March 2026, an increase of 6% from the previous quarter.
Average mobile broadband consumption increased from 14.6 GB to 15.1 GB per subscription, while 5G users recorded the highest average consumption at approximately 53.5 GB per subscription.
This growing appetite for data gives consumers another reason to maintain more than one mobile network.
A person might use one SIM primarily for calls and mobile money while using the other for particular data needs.
Safaricom Is the Main Number, Airtel Is the Alternative
The relationship can therefore be summarized quite simply.
| Need | Safaricom SIM 1 | Airtel SIM 2 |
|---|---|---|
| M-PESA | Very important | Alternative mobile money |
| Main telephone number | Common choice | Secondary number |
| Calls | Strong | Strong |
| SMS | Very strong | Alternative |
| Mobile data | Strong | Strong |
| Promotions | Regular | Competitive |
| Backup connectivity | — | Useful |
| Dual-SIM use | Primary | Secondary |
This does not mean every Kenyan uses Safaricom as SIM 1 and Airtel as SIM 2.
Some users prefer Airtel as their primary SIM. Others use Safaricom alone, while some use other operators such as Telkom, Faiba or Equitel.
The SIM 1/SIM 2 pattern is better understood as a reflection of the different strengths and consumer perceptions surrounding Kenya’s two largest mobile operators.
The Numbers Tell an Interesting Story
The CA’s latest figures show just how active Kenya’s mobile market is.
Between January and March 2026, total domestic mobile voice traffic reached 32.3 billion minutes. Safaricom accounted for approximately 21.0 billion minutes, while Airtel accounted for about 11.3 billion minutes.
The data also shows that Kenyans are increasingly moving toward faster mobile technologies.
The CA reported continued declines in 2G and 3G subscriptions as customers migrate to 4G and 5G.
This means the competition between Safaricom and Airtel is no longer simply about voice calls.
It is increasingly about data, smartphones, 5G, digital services and the overall customer experience.
Is Safaricom SIM 1 and Airtel SIM 2 the Best Combination?
For many Kenyan users, it can be a practical combination.
Safaricom can serve as the primary number because of its large customer base and M-PESA ecosystem, while Airtel provides another network for data, calls, promotions and backup connectivity.
But the “best” combination ultimately depends on where you live, your preferred bundles, network performance in your area and the services you use most.
For a heavy data user, Airtel may sometimes be the preferred primary SIM. For someone who relies heavily on M-PESA and Safaricom contacts, Safaricom may naturally remain SIM 1.
The Bigger Picture
The popularity of dual-SIM phones tells us something important about Kenya’s telecommunications market.
Consumers are becoming increasingly value-conscious and flexible.
They don’t necessarily want to remain completely loyal to one network. Instead, they can keep multiple SIM cards and use each operator according to their needs.
That competition is ultimately good for consumers because Safaricom and Airtel have to continue improving their:
- Network coverage
- Internet speeds
- Data packages
- Voice offers
- 4G and 5G services
- Customer service
- Digital products
As Kenya’s mobile data consumption continues to rise, the SIM 1/SIM 2 strategy is likely to remain common among smartphone users.
Conclusion
Safaricom SIM 1 and Airtel SIM 2 is more than a phone configuration—it reflects how many Kenyan consumers balance convenience, mobile money, connectivity, pricing and competition.
Safaricom’s enormous mobile and M-PESA ecosystem makes it a natural primary line for many users, while Airtel’s position as a major competitor gives consumers an attractive second option.
And with Kenya’s mobile subscriptions, smartphone adoption and data consumption continuing to grow, having two networks in one phone gives users something valuable: choice.
