The additional requirements will apply from Friday, October 16th in both cantons.
Cantonal authorities announced on Tuesday announced that the two German-speaking cantons would become the 13th and 14th to extend mask requirements beyond the federal minimum.
Schwyz has the second-highest number of new coronavirus infections over the past 14 days on a per capita basis, after the heavily-hit canton of Geneva.
In Schaffhausen, infections are also on the rise. The canton recorded the most coronavirus infections since the outbreak of the pandemic over the past week.
Where do I need to wear a mask in the two cantons?
Schaffhausen will require masks in shops, shopping centres and supermarkets from Friday until November 29th at the earliest.
Staff will not be required to wear masks, provided they are protected by a physical partition such as plexiglas.
Cantonal authorities said further restrictions may be necessary in Schaffhausen if the situation continued to worsen, such as masks required in all publicly accessible indoor spaces as well as at events.
In Schwyz, masks will be required at all public and private events with more than 50 people.
While it applies to shops and supermarkets – along with bars, restaurants, clubs, cinemas, post offices and places of worship – it will only apply where minimum distance cannot be kept.
In Schwyz, the number of coronavirus cases rose from 34 to 391 over the past 24 hours to Tuesday, October 13th.
A total of 12 people are currently quarantined in the canton.
Masks have been mandated on all public transport in Switzerland since July 6th, however all remaining restrictions have been left up to the cantons.