The tower was built about 700 years ago and is older than most other parts of the church, and older than most other church towers in Pembrokeshire. When first built it provided a belfry and a chapel, and could also serve as a lookout point and a place of refuge in troubled times. The spire was added about 200 years later, and its height (152ft.) makes it a notable landmark for travellers by land or sea.

The doorway into the stair turret from the churchyard was made in 1862 by enlarging a window opening, and the original doorway inside the church was blocked up. This was done because the rector at that time thought the bellringers often had too much to drink after ringing and disturbed the congregation. Halfway up the winding stone stair is a blocked doorway that formerly gave access to a rooftop within its church; it was reset here from another winding stone stair that was filled in when the spire was built in the late 15th Century.

The first-floor chamber, its stone floor resting on the vaulting of its ground floor, was originally a chapel which now serves as the ringing chamber. In the eastern window opening (the tallest one opposite the entry) the damaged altar slab remains though now covered by boarding, and to the right of it inside the wooden casing is a small pointed recess or piscina for altar vessels. The mechanism of the clock was installed in 1888 and until recently the three sets of weights had to be wound up by hand everyday; this is now done automatically by electric motors.

There was a clock in the tower in 1650 but it may not have had a dial and simply struck the hours. It was replaced in 1726 by a clock with one dial, and in 1813 two other dials were added. A new clock was provided in 1861 but the fourth dial was not added until the present clock replaced that one. The boards on the walls of the ringing chamber recording local charitable gifts used to be hung inside the church. Two of them were painted in 1703 and show the quaint spelling of that time. The heading "Benefactors of this corporation" shows how civic and church affairs were intermixed, the Town Council being responsible amongst other things for the maintenance of the church itself.

The stairs lead on up to the belfry where the eight bells hang in a wooden frame. Four of them were cast in 1789 as part of the a ring of six bells by William Bilbie of Chewstoke in Somerset, and the frame is mainly of this date. Each of them is lettered with the names of the churchwardens at that time: Thos. Saer and John Lock, and the tenor bell (the heaviest weighing over 12 cwt.) also has the inscription: "I to the church the living call and to the grave doth summon all". The two treble (or lightest) bells added in 1818 are by Warner of Birmingham, named and lettered respectively: Sanctus Georgius, Sanctus David, and Sancta Maria. The fourth bell was recast in 1951 by Taylor of Loughborough and is suitably lettered, the whole ring being then retuned and re-hung. A 15th-century bell that used to hang outside the north side of the spire now stands inside the church. IN 1659 there were five bells but several had to be recast before 1789 because they cracked.

Standing by the bells it is possible to look upwards and see the hollow interior of the spire almost to its full height. The stones on the inner faces are local limestones like the tower, but the outer faces are of a finer dressed stone brought from Somerset. Notice also how the angles of the tower are built across to produce the eight equal sides of the spire. The narrow belfry openings were meant to give protection rather than allow the sound of the bells to be opened out over the town.

The stairs continue up to the parapet walk at the top of the tower, 83ft. above the ground. The builders of the spire had to form the octagonal shape face the square top of the tower, and the spire base shows how ingeniously this was done. The top-most 8ft. of the stonework was renewed in 1963 and the weathercock restored and reguilded. This copper weathercock may well be the one set up in 1715 and often repaired afterwards. In 1894 it was blown off in a tremendous gale and landed in the harbour!

The view from the parapet gives a fine impression of the medieval town with its tightly packed houses, narrow streets, town wall and harbour. The more distant views show Caldey Island to the south with St. Margaret's Island partly hidden by Giltar Point; to the east, across Carmarthen Bay is Gower and Llanelli; to the north, Monkstone Point and Amroth; and to the west, the Ritec Valley and the Ridgeway with Penally nestling at its foot.