This investigation aimed to determine and correlate mean fibre diameter (MFD) and total follicle density (TFD) in juvenile (1–2 years) and adult (3–6 years) white and brown alpacas in the Parinacota Region of northern Chile. Fibre samples and skin biopsies were taken from the mid-side regions of 77 individuals. The observed MFD for all individuals (22.6±3.76 µm) was lower than that obtained by previous research in the same geographic region. There was no demonstrated statistical difference between MFD and TFD based on fleece colour (p>0.05). Demonstrated MFD in white alpacas was 22.57±3.92 µm with a TFD of 21.97±6.37 foll/mm2; in brown alpacas MFD was 22.63±3.66 µm and TFD 21.56±7.25 foll/mm2. MFD in juvenile alpacas was 21.61±2.78 µm with a TFD of 24.2±7.49 foll/mm2 and in adults MFD was 23.47±4.3 µm with a TFD of 19.62±5.34 foll/mm2, demonstrating a statistically significant difference between age groups of lower MFD but higher TFD in juvenile individuals (p<0.05). A correlation (−0.42, p<0.05) between lower mean fiber diameter and higher TFD was observed for all individuals. These results contribute to regional efforts to advance genetic selection based on TFD and improve fleece productivity and economic viability of the local industry.