How old should children be to have their first mobile phone? Research suggests that "starting at age 13" is best.

Philadelphia Children’s Hospital’s latest research gives parents a clear recommendation: children should wait until at least age 13 before being given their first smartphone. But the study also warns that the real risks are not only about “what age” they get it. For teenagers who use their phones more than 5 hours a day, the chances of developing depression, obesity, and insufficient sleep within a year are more than doubled.
(Background information: Japan is planning legislation to restrict teenagers’ use of social media, and the global regulatory wave continues to spread.)

Table of Contents

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• What the research says: age is a floor, not a ceiling
• Preliminary research: risks at age 12 are already foreseeable
• What parents can do: from age, to time, to space
• Policy waves: from Australia to the world
• The boundaries and limitations of age restrictions

The latest research from the team led by Ran Barzilay, an adolescent psychiatrist at Philadelphia Children’s Hospital, shows that children who got their first smartphone at age 12 have clearly higher risks of depression, obesity, and insufficient sleep one year later. By contrast, children who only received their phone at age 13 show “no association” with depression and obesity.

This new study, published in JAMA Pediatrics, analyzed 1,959 adolescents: 1,230 of them obtained their first smartphone between ages 13 and 14, while 729 did not. After tracking them for one year, the researchers’ core conclusion was: “13 years old” is a relatively safe starting age, but it is absolutely not a safety blanket.

What the research says: age is a floor, not a ceiling

Barzilay told Bloomberg, “13 feels safer. Even so, it’s still important to ensure children’s screen time is limited.” This captures the core message of the study: age restrictions are a necessary condition, but they are not a sufficient one.

The research data clearly demonstrate the importance of usage behavior: among teenagers who use smartphones more than 5 hours a day, within one year after getting their phones, the risk of depression, obesity, and insufficient sleep is “more than doubled.” Simply keeping the phone out of the bedroom can significantly reduce the risk of insufficient sleep.

Barzilay describes controlling usage time and location as “a very direct intervention or behavioral adjustment that can bring about very big changes.” The “intervention” he mentions refers to two specific approaches parents can take: explicitly setting a daily usage limit and banning phones from entering the bedroom.

Preliminary research: risks at age 12 are already foreseeable

This is not the first time Barzilay’s team has issued a warning. The earlier pilot study, published in Pediatrics, used data from the U.S. Adolescent Brain Cognitive Development (ABCD) database. It analyzed longitudinal data across 21 research sites, involving more than 10,588 adolescents, with five assessments from 2016 to 2022.

The results found that having a phone at age 12 was significantly associated with adverse health outcomes such as depression, obesity, and insufficient sleep. The new study further narrowed the focus to “age 13 vs. no phone,” confirming the significance of the age threshold while also highlighting the central role of behavioral regulation.

The message conveyed by the two studies together is: “Age restrictions alone can’t rescue you from smartphone-related risk.” This is also the core point the research team proactively shares with the media.

What parents can do: from age, to time, to space

In addition to delaying when children receive a phone, the research points to three concrete operational areas:

• Time limits: set a daily usage cap and avoid the high-risk window of exceeding 5 hours
• Space limits: keep the phone out of the bedroom to protect sleep quality
• Collective action: the “Wait Until 8th” pledge movement encourages parents to collectively agree not to give children smartphones before the end of eighth grade, reducing the “follow-the-crowd giving” phenomenon driven by peer pressure

For parents who want their children to stay in touch but do not want to give them smartphones, “dumb phone” alternatives with limited functions have also appeared on the market—such as Tin Can—offering only calling and text messaging functions, and not featuring social media, video, or gaming applications.

Policy waves: from Australia to the world

The timing of the study’s release coincides with governments in various countries accelerating their legislative steps. On December 10, 2025, Australia officially implemented the world’s strictest adolescent social media ban, prohibiting users under 16 from holding social media accounts. Enforcement is handled by eSafety Commissioner Julie Inman Grant, and violating platforms may be fined up to about 50,000,000 Australian dollars. By mid-December, about 4.7 million underage accounts had been removed.

Australia’s approach has already prompted other countries to follow suit and reassess: France, by banning social media use for under 15s (parents may consent for use starting at 13); Denmark is drafting a ban for under 15s; Portugal is restricting for under 16s; Indonesia and Malaysia both plan to ban for under 16s, with Malaysia expecting to officially roll out the policy starting in 2026.

The boundaries and limitations of age restrictions

While the research provides policy support, it also clearly lays out the limits of this legislative push. Barzilay’s research indicates that the risk of depression is not only related to “what age” a child gets a phone; it is also directly linked to “how long” they use it each day and “where” they use it. This means that even if legislation successfully raises the age for receiving a phone to 13—or even 16—if there is no family-level management of usage behaviors, the risks will not automatically disappear.

In simple terms: age restrictions are the floor for opening the right conversation, but true protection is in the ceiling—how many hours a day, and where the phone is placed. The study’s numbers (the 5-hour threshold and the effect of bedroom restrictions) give parents and policymakers more actionable guidance than just “what age.”