Bread wheat is a moderately salt tolerant crop, able to maintain low leaf sodium (Nat) due to shoot Nat exclusion mechanisms. Many of the mechanisms behind shoot Nat exclusion in bread wheat are known, with significant research focused on enhancing bread wheat’s Nat exclusion mechanisms. However, Nat exclusion from the shoot is only one mechanism for salinity tolerance and is not 100% effective when exposed to salinity for long periods. Ultimately, Nat will accumulate to toxic levels in leaves, resulting in enhanced senescence and reduced crop yield. The introduction of shoot Nat tissue tolerance mechanisms, in addition to bread wheat’s shoot Nat exclusion mechanisms, would considerably enhance the growth and yield of wheat in saline soils. We have identified a Portuguese landrace, Mocho de Espiga Branca (Mocho), which is able to accumulate barley levels of leaf Nat (10X that of bread wheat). We show Mocho’s inability to exclude Nat from leaves is due to a single amino acid change in the Nat transporter HKT1;5-D, making it incapable of retrieving Nat from the root xylem. Despite lacking a functional HKT1;5-D and accumulating 10 × as much leaf Nat as conventional wheat cultivars, Mocho has similar or higher salinity tolerance as conventional elite Australian bread wheat suggesting that is has good tissue tolerance mechanisms. Further investigation of these tissue tolerance mechanisms has revealed the processes that are not involved in Mocho’s tissue tolerance. Convention would suggest Mocho must compartmentalise Nat in the leaf vacuole and balance the osmotic potential between the cytosol and vacuole through the synthesising compatible solutes. However, we have found no difference in compatible solute accumulation between Mocho and wheat cultivars which accumulate a tenth of the shoot Nat. Another explanation is required. Additionally, we have also observed no difference in grain Nat concentration between Mocho and wheat cultivars which accumulate a tenth of the leaf Nat, suggesting that Mocho can control loading of Nat into the grain. Work will be presented regarding the progress of characterising Mocho’s shoot Nat tolerance mechanisms using both forward and reverse genetic approaches.