For information on aftermarket keycaps, see Keycaps.
Happy Hacking Professional keyboards, and Topre-manufactured keyboards in general, are known for their high quality OEM keycaps. All HHKB Pro keycap sets are made of PBT (polybutylene terephthalate), a durable plastic that resists wear and doesn't yellow over time (unlike ABS). The historical exception was the spacebar, made of ABS on all HHKB Professional models until the HHKB Professional Hybrid series.
OEM Full Keysets
|PD-KB400KTB||Yes||Charcoal||ANSI (60 keys)||ABS spacebar|
|PD-KB400KTBN||No||Charcoal||ANSI (60 keys)||ABS spacebar|
|PD-KB400KTW||Yes||White/Grey||ANSI (60 keys)||ABS spacebar|
|PD-KB400KTWN||No||White/Grey||ANSI (60 keys)||ABS spacebar|
|PD-KB420KTB||Yes||Charcoal||JIS (69 keys)||Japan-only|
|PD-KB420KTW||Yes||White/Grey||JIS (69 keys)||Japan-only|
|PD-KB400KTYN||No||Snow White||ANSI (60 keys)||Japan-only|
|PD-KB420KTYN||No||Snow White||JIS (69 keys)||Japan-only|
OEM Partial Keysets
|Both||Red/Blue||All||Printed/non-printed red control and blue Escape||Limited release in US, still sold in Japan|
|PD-KB400KT02||Both||Blue/Green||All||Printed/non-printed blue control and green Escape||Japan-only|
|CG01000-302701||Yes||Charcoal||All||25th Anniversary Fn keycap||Limited edition (link)|
|CG01000-302601||Yes||Gray||All||25th Anniversary Fn keycap||Limited edition (link)|
Topre has also released keycap sets intended for use on their Realforce line of keyboards. These sets nearly support the HHKB line with the exception of the right Shift key. For blank sets, the space Caps Lock key can be used for the right shift key as long as you don't mind the slight difference in profile.