In 1954, ownership of Enders Island was transferred from Alys Enders to the Society of St Edmund. The deed stipulated that Enders Island be used solely as a novitiate and a retreat for priests of the Archdiocese of Norwich. The deed further stipulated that Enders Island be returned to the estate of Alys Enders if those uses ceased.

In 2003, ownership of Enders Island was transferred from the Society of St Edmund to St Edmund of Connecticut, Inc., an independent non-stock corporation. The deed stipulates that St Edmund of Connecticut abide by all conditions, covenants and restrictions as may be binding on the property, i.e. the restrictions contained in the deed conveying Enders Island to the Society of St Edmund.

Prior to the transfer of Enders Island to St Edmund of Connecticut, a prominent Catholic ethicist was asked to review the proposed transfer and offer his opinion on the matter. The ethicist found that the Society of St Edmund "had a substantial obligation to respect her [Aly Enders] wishes" and "has as an ethical obligation to require that Mrs. Enders' conditions about the use of the island be placed in any deed which would transfer the property".

In 1920, Masons Island Company granted T. B. Enders a right-of-way through Masons Island. The agreement permitted ingress, egress, and regress to Enders Island. The agreement did not contemplate non-residential use of Enders Island.

The last will and testament of Alys Enders describes how the remainder of her estate should be distributed, including Enders Island should it revert to the estate. It is divided into four groups. Those groups include individuals as well as charitable organizations including Lawrence and Memorial Hospital, Memorial Hospital of New York, the Boy Scouts, the Girl Scouts, and Mystic Seaport.

The codicil to the last will and testament of Alys Enders further clarifies how her estate should be distributed and managed. Once again, it includes Lawrence and Memorial Hospital, Memorial Hospital of New York, the Boy Scouts, the Girl Scouts, and Mystic Seaport