
Yes, you need a certificate of sponsorship from a licensed scheme operator, and you generally cannot switch into this route from another visa inside the UK.
The Seasonal Worker visa is a sponsored route, so you must have a valid certificate of sponsorship from an approved scheme operator before you apply. You will also need to meet the financial requirement to show you can support yourself on arrival.
As a temporary, entry-focused route, it is normally applied for from outside the UK rather than switched into from another visa. If you are already in the UK on a different visa and want seasonal farm work, check the GOV.UK rules carefully, as switching into this category is generally not permitted.
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