Ayyā Nimmalā Bhikkhunī (Cathy Meadowcroft), a native Canadian, began her journey into Buddhist monasticism by serving as a steward first at Birken Forest Monastery and later at Tisarana Buddhist Monastery where she was guided by dedicated teachers including Ajahn Viradhammo, Ajahn Sona and Ajahn Kusalo.
In 2010, she received ordination as a sāmaņerī Buddhist nun with Ayyā Medhānandī as her ācarinī (teacher).
In 2011, she deepened her commitment and became a bhikkhunī at Spirit Rock, California with Ayyā Ānandabodhī and Ayyā Santacittā of Aloka Vihāra. The bhikkhunī upasamapda ceremony was performed by a dual Theravāda Sangha of bhikkhus and bhikkhunīs lead by Ayyā Tathālokā Therī, acting as pavattinī (preceptor).
Ayyā Nimmalā worked with Ayyā Tathālokā to co-edit the 3rd edition of the Pāli-English Bhikkhunī Pātimokkha booklet, printed in 2016 for distribution to the Bhikkhunī Sangha worldwide.