There is no public parking available at the church.
Please take care to read the notices when using on street parking as restrictions vary from street to street and some roads become residents' permit parking in the evenings and at weekends. There are pay and display parking bays in Claremont Road, Dorset Road and Alma Road (and further) - some of the parking bays near the church are for residents only. Depending on the service you are attending please consider whether you are likely to encounter road closures or security restrictions.
Blue badge holders can park on double yellow lines if you are not causing an obstruction (and there are no road closures/security restrictions).
There are several car parks in Windsor - for a more comprehensive list please see the Royal Borough of Windsor & Maidenhead website http://www.rbwm.gov.uk/web/parking_windsor_area.htm (Holy Trinity is the middle of what appears to be a roundabout (it isn't when driven) at the bottom centre of their map).
The East Berkshire College car park is situated beside the church and is a public car park only at weekends and during college holidays.
Alma Road Overflow car park has the same restrictions as the East Berkshire College car park and is signed from Alma Road (however the sign is sometimes covered by trees!) - enter 67 Alma Road (offices) down the side of Connaught Court (flats) and turn right at the roundabout, go straight on for the car park.
Victoria Street multistorey (entrance is in Russell Street (one way) - turn off Victoria Street into Alexandra Road and right again into Russell Street).
A little further away but only a few minutes' walk is the council office car park, York House, in Sheet Street which is available for public use outside office hours.
These car parks are RWBM pay & display.
There is also a private car park in the shopping centre, King Edward Court - the entrance is in Charles Street (no right turn - so access from Arthur Road, Goswell Road or if coming from the other direction make a U at the roundabout).
This information is not intended to be comprehensive and is correct to the best of our knowledge at the time of posting - you may wish to verify it by checking the council website etc..