 On 10 May 2016, he was included in the final South Africa Under-20 squad for the 2016 World Rugby Under 20 Championship.mutambo uchaitirwa muManchester, England. Akatanga mutambo wavo wekuvhura muPool C yemutambo uyu sezvo South Africa yakauya ichibva kumashure kuti ikunde Japan 5919, uye vakatamba kunze kwebhenji mumutambo wavo unotevera wedziva sezvo South Africa yakarohwa 1319 neArgentina. Akadzoserwa kumutsara wekutanga wemutambo wavo wekupedzisira weboka, sezvo South Africa yakadzoka kubva pakukundwa kwavo kuti vawane 40-31 bhonasi-poindi yekukunda France kuti vawane nzvimbo yehafu-yekupedzisira semumhanyi akanakisa mumakwikwi. Akatanga semi-fainari, apo South Africa yakatarisana neEngland yakatamba makwikwi matatu. Makwikwi aya akaratidza kuva akasimba zvikuru kuSouth Africa, ichivasiya kunze kwemakwikwi aya nekukunda 39-17. Jackson akatangawo kurwisa Argentina mumutambo wechitatu-wechitatu, asi vakatambura kukundwa kwavo kwechipiri kuArgentina mumutambo, vachigutsikana nekurohwa 4919 kuti vapedze panzvimbo yechina mumakwikwi. 