In a bowl or coffee press, add Thai tea mix and hot water. Steep for 3 minutes. Strain out tea leaves with a tea strainer or coffee press and pour brewed tea into a cup.
Make Dalgona Tea
In a mixing bowl, add instant coffee, sugar, and brewed tea. Using a hand mixer with whisk attachment, mix on low speed until incorporated. Then turn up hand mixer to medium to high speed until dalgona Thai tea mixture increases in volume and turns a light orange color. Keep mixing until the creamy mixture fluffs up even more and has stiff peaks.
In a cup, pour in milk and (optional) ice, leaving at least half the cup empty for the Dalgona mixture. Scoop in Dalgona Thai tea mixture onto the milk. Serve and enjoy.