Spy x Family: Sub or Dub?
Megan Shipman says the English actors watch every Japanese line before recording their own. Here are the checked casts and a fair way to compare them.
Watch Spy x Family in English if you want Anya's comedy without reading under it; choose Japanese if Atsumi Tanezaki's Anya is the performance you came for. The most useful evidence about the English track comes from its own Anya, Megan Shipman, who has said the English actors watch each Japanese line before recording their own. That makes this an unusually direct comparison: by her account, the English Anya starts from the Japanese performance.
Who plays whom?
ANN's encyclopedia credits the Japanese leads as Takuya Eguchi as Loid Forger, Saori Hayami as Yor Forger and Atsumi Tanezaki as Anya Forger, with Kenichirō Matsuda as Bond. The English cast it lists is Alex Organ as Loid, Natalie Van Sistine as Yor, Megan Shipman as Anya and Tyler Walker as Bond, with Cris George as ADR director. Both casts are on ANN's season 1 entry.
The series is made by Wit Studio and CloverWorks, which ANN lists as the animation producers. You are comparing two voice tracks laid over the same pictures, so the timing of every visual joke is fixed before either cast speaks.
Where both tracks are available
Crunchyroll's announcement for season 2, reprinted by ANN, said the season would stream "only on Crunchyroll" and "be subtitled and dubbed in all of its territories," with an English dub among nine dub languages and dub dates announced later. The press release covers season 2; check the listing on your own service for the season you are watching, because availability is set per region.
What the English Anya says she listens to
Talking to CinemaBlend's Alexandra Ramos, Shipman credited the writing and translation, then explained her method: "we watch every line before we record our own." She described hearing a Japanese take, finding it funny, and realizing she had to be that funny too. The interview also has her insisting that Anya, telepathy and all, is still written as a child.
That is an account of method, not a verdict. It tells you Shipman starts from Tanezaki's performance rather than recording without it. It does not tell you the English jokes land the same way, and nothing here proves they do.
A fair way to compare
Pick one of Anya's reaction moments early in season 1 and play it in both languages. Ask which version lets you watch her face instead of the subtitle line, and whether the joke survives that. Then try a scene that belongs to Loid or Yor, because a show with three leads is not decided by one of them.
English is the practical choice if you want to watch the faces rather than the subtitles. Japanese is the direct route to the performances the English cast studied. Keep the watch order for where Code: White fits, and see the manga if you want Anya's lines on the page.