Although the feast day of St James is celebrated on 25 July on the liturgical calendars of the Roman Catholic, Anglican, Lutheran and certain Protestant churches, he is commemorated on 29 April in the Orthodox Christian liturgical calendar. Those churches which follow the traditional Julian Calendar, 30 April currently falls on 13 May of the modern Gregorian Calendar.
So, happy St James' Feast Day to our orthodox Christians!
In the early middle ages the 30 December was St James’ Feast day, based on the old Hispanic (Mozarabic) rite.
In the 11th century King Alfonso VI abolished the Hispanic rite in favour of the Roman rite and July 25 became the principal feast day to commemorate the martyrdom of St. James. December 30 was incorporated into the present liturgical calendar as the Feast of the Translation of his relics.
Although we celebrate his Feast Day on 25th July, using the Roman Rite calendar, it was formerly on the 5th August on the Tridentine Rite calendar.
But don't despair, the plenary indulgence is given, not only in Holy Years, but also in ordinary years on Easter Sunday; 21st April (the anniversary of the consecration of the cathedral); and on St James's three feast days. (25th July, 30 December and 23 May) - but not on 30th April or 13 May.