Passport photos rank among the least flattering images most people own — dull lighting, restrictive rules, and, notably, the absence of a smile. While many travellers assume smiling is outright banned, experts clarify that the restriction exists for one primary reason: global security protocols driven by facial-recognition technology.

Why smiling complicates passport verification

According to the United States Department of State, smiling is not technically prohibited, but passport applicants must maintain a neutral expression with eyes open and mouth closed. This subtle distinction exists to ensure border-control systems can correctly match a traveller’s face to their document.

Biometric specialist Karolina Turowska explained that algorithms measure key facial markers — including pupil distance, eye width, and the relative position of the nose and mouth. “A broad smile alters facial proportions and makes matching far more difficult,” she noted. While humans recognise faces easily, machines require consistency.

Travel expert Katy Nastro added that wide smiles make it harder to verify eye colour and facial shape. With most international airports now relying heavily on automated biometric checks, consistency in passport photos is critical.

A universal rule shaped by global standards

Many countries follow similar regulations, guided by the International Civil Aviation Organization (ICAO), which standardises global passport requirements. Nations such as France enforce even stricter rules, forbidding even slight smiles.

Passport photos were far less regulated a century ago. Early passports sometimes included individuals posing with musical instruments or wearing decorative hats. However, as global travel expanded and international security grew more complex, stricter rules became essential.

What happens if you submit a smiling photo?

Improper photos are among the most common reasons for passport application delays. If a picture shows a broad smile or visible teeth, authorities will request a replacement, leaving the application on hold until a compliant image is provided.

Other restrictions also apply:

  • Eyeglasses are disallowed unless medically necessary.
  • Hats and head coverings require proof of religious or medical need.
  • No frowning, exaggerated expressions, or crinkling.

Children receive some leniency, though their facial features must remain recognisable.