The Victorians, of course, were influenced by the Romantics, and Romantic poets such as Wordsworth lived long enough to be writing into the Victorian age. However, that being said, Dylan Thomas definitely captures the fire of the early Romantic poets.
A poem such as "Do Not Go Gentle into that Good Night" records the personal emotions of the poet, one of the aims of Romanticism. It is about an ordinary person—also a theme of Romantic poetry—presented in a positive light as the speaker cries out to his father to "rage, rage" against dying. We feel the deep intensity of the the speaker's love for the father and his deep emotional desire that he fight with all he has to stay alive.
A poem like "Fern Hill" celebrates natures, a theme of Romanticism, and more importantly, is Romantic in its recollection of idyllic childhood as the speaker returns to the place where he was happy and carefree as a youth. The poem is evocative of Wordsworth as it describes emotions recollected in tranquillity, triggered by returning to a childhood setting. Dylan writes in glowing terms about nature as he remembers it:
All the sun long it was running, it was lovely, the hay/ Fields high as the house, the tunes from the chimneys, it was air /And playing, lovely and watery /And fire green as grass.
The verses carry the excited emotional cadences of childhood. The excitement of Thomas's poetry and its felt emotion, is reminiscent of the emotional intensity of Romantic poetry at its finest. It also uses the simple, everyday language of the Romantics.