A 3 × 2 factorial experiment was conducted to investigate the effects of different ratios of dietary laminarin (LAM) and fucoidan (FUC) on growth performance and nutrient digestibility in newly weaned piglets. At weaning, 168 piglets (24 d of age; 6.8 kg live weight) were assigned to 1 of 6 dietary treatments (n = 14/treatment): (i) basal diet, (ii) basal diet + 240 mg/kg FUC, (iii) basal diet + 150 mg/kg LAM, (iv) basal diet + 150 mg/kg LAM and 240 mg/kg FUC, (v) basal diet + 300 mg/kg LAM, and (vi) basal diet + 300 mg/kg LAM and 240 mg/kg FUC. Pigs offered 300 mg/kg LAM-supplemented diets had a higher ADG (P < 0.05) throughout the entire experimental period (days 0-35) compared with pigs offered diets with 0 and 150 mg/kg LAM supplementation. There was a significant interaction between LAM and FUC supplementation on G:F (P < 0.05) during the entire experimental period. Pigs offered the 300 mg/kg LAM-supplemented diet had a higher G:F than pigs offered the basal diet. However, there was no effect of the high level LAM on G:F when combined with FUC. There was a significant interaction between LAM and FUC supplementation on the apparent total tract digestibility (ATTD) of GE (P < 0.05). Pigs offered the 150 and 300 mg/kg LAM diet had an increased ATTD of GE compared with pigs offered the basal diet. However, there was no effect of LAM on ATTD of GE when combined with FUC. Pigs offered the 150 and 300 mg/kg LAM-supplemented diets had an improved fecal consistency (P < 0.05) from day 7 to day 14 compared to pigs offered diets without LAM supplementation. In conclusion, the inclusion of LAM improved growth performance of pigs after weaning partially due to an increased ATTD of GE.