Nationals of most Commonwealth countries may enter Lesotho without a visa. Those of a few countries such as Australia, Canada, and New Zealand, may not. Nationals of Denmark, Finland, Ireland, Israel, Japan, Norway, South Africa and a few other countries do not require visas. All others are required to have a visa to enter the country. You'll need a multiple-entry visa in order to re-enter South Africa, if you will initially be going into Lesotho from the Republic of South Africa. It is advisable to check for the latest visa requirement information with the Lesotho representative in your country.
Lesotho Embassy in the USA
Lesotho High Commission in the UK
Lesotho Embassy in Ireland
Lesotho missions abroad