The Spectacles glasses were previously available only from pop-up vending machines in US cities.

The rollout comes ahead of Snap's initial public offering on the stock market.

One industry analyst said the move would help sustain interest in the company, which could be "helpful" for its IPO.

"The way they sold them to start with was an incredible way of creating a buzz around a new product, especially among the engaged Snapchat audience," said Ben Wood, of the CCS Insight consultancy.

"The exclusivity associated with Spectacles made them bigger than if they had just been put up for sale on a website.

"But it has also given them opportunity to ramp up volume and refine the product, before launching a bigger distribution online with more confidence."

Mr Wood said the product was part of Snap's move to expand beyond being a messaging app company.

It is facing tough competition from Facebook, which has replicated some key Snapchat features in its Instagram and Messenger apps.

"If the Spectacles are successful, it will help position Snap as a camera company, which is a key pillar of their business," said Mr Wood.

"They're perceived as a fun product, which helps resonate that Snap is trying to offer something different to Facebook. It adds diversity to its business."

Snap is seeking a valuation of up to $22bn (£17.5bn), despite making losses.