Finnish-American smart ring maker Oura Health has unveiled its latest device, the Ring 5, as the company accelerates product innovation ahead of a widely anticipated initial public offering later this year.

The company, known for popularising the smart ring category and attracting a strong following among celebrities and athletes, said the new model is its smallest and most advanced wearable to date.

The Ring 5 is 40 per cent smaller than its predecessor, the Ring 4, and features improved battery life despite its reduced size.

Measuring just 2.28mm thick, the device is designed to deliver advanced health-tracking capabilities in a more discreet, jewellery-like form.

Oura said the ring focuses on core biometric insights including sleep quality, stress levels, readiness scores, and cardiovascular health, positioning it as a compact alternative to traditional smartwatches.

“The [Ring 5] is the most capable wearable we’ve ever made – small enough to fit seamlessly into everyday life, and significant enough to set a new standard,” said Holly Shelton, Oura’s chief product officer.

Oura is banking on its fifth-generation smart ring to reinforce its leadership in a fast-growing category while broadening its appeal to users who have been deterred by bulkier devices or less subtle wearable designs.

The Ring 5 will start at £399 (€399/$399/$A649) when it ships on 4 June, alongside a £5.99 (€5.99/$5.99/A$9.99) monthly subscription required to access its full suite of health-tracking features.

Founded in 2013 in Oulu, Finland, Oura Health has been a key driver in shaping the smart ring market.

The category continues to expand rapidly, with about 4 million devices shipped in 2025, more than doubling over each of the past two years, according to analyst data from FDM CCS Insight.