The answer is to wear a vest as it is known in Savile Row. A waistcoat to most. Regrettably with central heating and a more relaxed look nowadays the 3 piece suit is not as popular as it once was. The top pocket of a four pocket vest is by far the most practical and comfortable way to carry a smartphone upon your person. No unsightly bulges in trouser or jacket pockets one so often sees. Furthermore the top vest pocket is the most secure place. I prefer to slip my phone into my top right pocket. Furthest away from my heart. Those with implanted heart hardware may wish to consult their physician. Furthermore, calls are easily identified by ring tone and/or vibration.
So perhaps the vest (waistcoat) may make more of a return.
This one pictured is a vest from one of my Huntsman of Savile Row 3 piece suit collection. Made in 1986 and still in perfect condition.
Bespoke Huntsman, Savile Row, Solaro suit. Bespoke Turnbull & Asser cornflower blue shirt with French cuffs. Hermes silk ‘snail’ tie. Turnbull & Assser silk pocket square. Edward Green suede tassel loafers.
The Huntsman Solaro is 11 oz. Iridescent olive green herringbone with the classic red weft showing through. This is evident in the penultimate photo of the inside leg of the photograph.
This Solaro suit was made for Walter Charles Lees. More information about the fascinating life of this gentleman may be obtained on the following link.
Please see below a very detailed account of the Solaro fabric history. I am most appreciative to Torsten of Sartorial Notes.