Providing dairy cows access to pasture is desirable, but farmers can face a range of practical constraints including the lack of available pasture. A possible alternative to pasture is a bedded outdoor area that requires less space than pasture. However, little is known about space requirements for outdoor packs. This study investigated how space allowance on an outdoor open pack affected the number of agonistic interactions on the pack and the time cows spent outdoors. Seventy-two pregnant, lactating, healthy Holstein cows were assigned to 3 groups (24 animals/group). At the start of each group, animals were given 3 d to allow for the social dynamics of the group to stabilize. Thereafter, a habituation phase of 5 d followed in which animals were given access to the outdoor pack with a space allowance of 16 m² per cow. After this habituation period, 13 different space allowances were tested differing in 1-m² increments, ranging from 4 to 16 m² per cow. Each group was tested for 1 d on each treatment, with treatments allocated randomly without replacement. The location of animals (i.e., in the freestall barn or on the outdoor pack) and displacements from a lying position on the outdoor pack were scored using continuous video observations. Data of the effect of space on time spent outside were analyzed using a mixed model that specified cow within group as a random effect; the same model with group as random effect was used to analyze the effect of outdoor space on the amount of agonistic interactions on the pack. Cows spent on average (±S.D.) 4.7 (±0.8) h/d outside, and spent more time outside with increasing outdoor space allowances (3.3 ± 1.2 min/m² increase). On the outdoor pack, cows engaged in a total average of 0.11 (±0.05) interactions/h outside, and this was not influenced by space. These results suggest that a bedded pack can be used to provide freestall-housed cows free access to the outdoors, with cows spending an increasing amount of time outside with increasing outdoor space allowance.