May a Catholic have thier cremated remains poured out at sea? My mother, a Roman Catholic in good standing, passed recently and wished to be cremated and her ashes poured out at sea.  A young priest at her parish, fresh out of seminary, indicated that such a thing goes against Catholic teaching while an older priest of 44 years in the same parish suggested not bringing the ashes to the memorial Mass and then doing whatever we wish.  It was also suggested that the entire urn could be tossed into the ocean but sprinkling the ashes out is the part that is disallowed.
What is the official Roman Catholic stance on:

Cremation
disposition of ashes at sea, particularly regarding sprinkling out of the urn
May Catholics have thier cremated remains poured out at sea?
The short answer is no.
Anyone familiar with the Catholic Church knows that over the years, they have changed their policies many times on numerous subject matters. And cremation is no exception. Burial of the human body is still the preferred manner.
In 1917, the code of Canon Law allowed cremation only in times of plague, disaster, or other situations that necessitated a quick disposal of the body.
In 1963, the Vatican said burial of deceased bodies should be the norm, but cremation is not “opposed per se to the Christian religion.” Catholic funeral rites should not be denied to those who had asked to be cremated, the church said.
Human ashes are to be buried at a Cemetery, just like as if the human body of the faithful departed were actually still present.
Catholics may choose to be cremated and has all the funeral rites of the Church, unless the reason for the cremation ”of their bodies for reasons contrary to Christian faith”.

Those to Whom Ecclesiastical Funerals Must be Granted or Denied
Can. 1183 §1. When it concerns funerals, catechumens must be counted among the Christian faithful.
§2. The local ordinary can permit children whom the parents intended to baptize but who died before baptism to be given ecclesiastical funerals.
§3. In the prudent judgment of the local ordinary, ecclesiastical funerals can be granted to baptized persons who are enrolled in a non-Catholic Church or ecclesial community unless their intention is evidently to the contrary and provided that their own minister is not available.
Can. 1184 §1. Unless they gave some signs of repentance before death, the following must be deprived of ecclesiastical funerals:
1/ notorious apostates, heretics, and schismatics;
2/ those who chose the cremation of their bodies for reasons contrary to Christian faith;
3/ other manifest sinners who cannot be granted ecclesiastical funerals without public scandal of the faithful.
§2. If any doubt occurs, the local ordinary is to be consulted, and his judgment must be followed.
Can. 1185 Any funeral Mass must also be denied a person who is excluded from ecclesiastical funerals.

According to new guidelines from the Vatican’s doctrinal office, cremated remains should be kept in a “sacred place” such as a church cemetery.
The following rules were issued on August 15, 2016 by the Vatican:

The reservation of the ashes of the departed in a sacred place ensures that they are not excluded from the prayers and remembrance of their family or the Christian community. It prevents the faithful departed from being forgotten, or their remains from being shown a lack of respect, which eventuality is possible, most especially once the immediately subsequent generation has too passed away. Also it prevents any unfitting or superstitious practices.

For the reasons given above, the conservation of the ashes of the departed in a domestic residence is not permitted. Only in grave and exceptional cases dependent on cultural conditions of a localized nature, may the Ordinary, in agreement with the Episcopal Conference or the Synod of Bishops of the Oriental Churches, concede permission for the conservation of the ashes of the departed in a domestic residence. Nonetheless, the ashes may not be divided among various family members and due respect must be maintained regarding the circumstances of such a conservation.

In order that every appearance of pantheism, naturalism or nihilism be avoided, it is not permitted to scatter the ashes of the faithful departed in the air, on land, at sea or in some other way, nor may they be preserved in mementos, pieces of jewelry or other objects. These courses of action cannot be legitimized by an appeal to the sanitary, social, or economic motives that may have occasioned the choice of cremation. - Instruction Ad resurgendum cum Christo regarding the burial of the deceased and the conservation of the ashes in the case of cremation



Ps. Unless one can find a Vatican directive allowing a complete urn to be cast into the sea, in lieu of sprinkling the ashes over the water, this is to be forbidden. Urns will crack and the remains will be scattered in the waters anyway. Without a clear Vatican directive this should not be done, regardless of what some Catholic priest or even Catholic websites states. We can not presume permission to so. They must always be able to back it up in Canon Law! Urns are to be buried in cemeteries.
Articles of interest:

Cemetery aims to 'do the right thing' with free burial
New Vatican Instruction: Cremation Allowed But Strict Conditions Apply
Why does the Catholic Church prefer burials over cremation?