Folkestone Bathing Explained
In a Ward Lock & Co. Guide Book dated 1929, they have a section on bathing for the tourist:

The beach is shingly, but at low tide a fair stretch of sand is exposed, and this has been increased in recent years by the use of cunningly-placed groynes.  The water is remarkably clear, and recedes only some 50 ft.

Visitors have a choice of several modes of bathing.  The usual charge is 9d., with an additional 2d for a costume and 1d for towels, if these are hired.

Eastward of the Victoria Pier and also near the tollgate on the Lower Sandgate Road (convenient for residents in the western part of the town) are large Bathing Pavilions, with commodious and well-fitted dressing rooms for both sexes.  The principal or Eastern Pavilion is open from 6 a.m. to 6 p.m. on weekdays; on Sundays from 6 a.m. to 12:30 p.m. and if fine from 2:30 to 4:30 p.m.  The Western Pavilion is open weekdays from 6 a.m. to 5 p.m., and on Sundays from 6 a.m. to 12:30 p.m.  At each of these stations a portion of the ground is appropriated to mixed bathing.  On a portion of the beach below the Metropole Lift,  bathing from tents is permitted.  For each tent a payment of 2s 6d for the season must be made at the Manor Office.  The tents can be stored on the spot for 1s 6d per week or 10s for the season.  Tents can also be hired at an inclusive charge of 10s per week.

Men in boats are stationed at various parts of the shore in readiness to assist bathers should they get into difficulties.

Close to the foot of the Eastern Lift and the Victoria Pier is a large Bathing Establishment, open during the season from 7 a.m. to 6:30 p.m.  Sundays 7 a.m. to 12 noon.  Here, in addition to tepid sea water swimming baths, can be had private sea or fresh water baths, warm or cold, shower baths, ozone baths, etc.  One swimming bath is for ladies and one for mixed bathing.

The charge for the swimming baths is 1s., 12 tickets 10s.; 12 club tickets 8s.;  for boys under 14,  6s. For a private hot bath, 1s. 6d.; cold 1s.  Folkestone Swimming Club - Ladies, Monday evenings, 7 to 9:30; gentlemen, Thursday evenings 7 to 9:30.  The establishment includes a refreshment room.

Near the western lift are bathing cabins, let for a period.

In Foord Road are Public Baths, open during the summer from 7 a.m. to 7 p.m. except Tuesdays, 7 to 12:30 p.m. only, and Sundays, men only 6 to 9 a.m.  The winter hours are shorter.

This still leaves me with a couple of questions.  Why the special rate for boys under 14?  What about girls under 14?  Also, they didn't mention Fagg's Safety bathing carriage, maybe it wasn't in operation by 1929.