NetBSD calls a supported architecture a 'port'. Most ports run on generic hardware and emulators, although some commercial hardware also exists. The NetBSD Ports History page details the inclusion date for each port.

Ports are classified into three 'tiers' based on the current importance of the architecture and the level of community activity. Summarizing, the tiers can be viewed to represent ports that NetBSD will support, ports that NetBSD does its best to support, and ports which may be desupported soon. The tier for each port may change over time and is decided by based on input from users and developers.

Tier I: Focus -- support is part of NetBSD's strategy

Focus ports are the architectures that NetBSD targets as part of its strategy.
The platforms consist of modern server, embedded and desktop architectures.

The guidelines are as follows:

Currently there are 8 ports with Tier I status. They are:

Port CPU Machines Latest Release
aarch64 aarch64 64-bit ARM CPUs 10.0
amd64 x86_64 64-bit x86-family machines with AMD and Intel CPUs 10.0
evbarm arm ARM evaluation boards 10.0
evbmips mips MIPS-based evaluation boards 10.0
evbppc powerpc PowerPC-based evaluation boards 10.0
hpcarm arm StrongARM based Windows CE PDA machines 10.0
i386 i386 32-bit x86-family generic machines ("PC clones") 10.0
sparc64 sparc Sun UltraSPARC (64-bit) 10.0
xen i386, x86_64 Xen Virtual Machine Monitor 10.0

Tier II: Organic -- evolving at its own pace

Organic ports are highly valued by the NetBSD project, but their development is not as tightly mandated as that of the focus ports. Generally speaking, the hardware platforms of organic ports have lost their industrial relevance, or there is not enough community activity for the port to make it to the first tier. The guidelines are as follows:

Currently there are 49 ports with Tier II status. They are:

Port CPU Machines Latest Release
acorn32 arm Acorn RiscPC/A7000/NC and compatibles 8.1
algor mips Algorithmics MIPS evaluation boards 10.0
alpha alpha Digital Alpha (64-bit) 10.0
amiga m68k Commodore Amiga, MacroSystem DraCo 10.0
amigappc powerpc PowerPC-based Amiga boards 10.0
arc mips Machines following the Advanced RISC Computing spec 10.0
atari m68k Atari TT030, Falcon, Hades 10.0
bebox powerpc Be Inc's BeBox 10.0
cats arm Chalice Technology's Strong Arm evaluation board 10.0
cesfic m68k CES's FIC8234 VME processor board 10.0
cobalt mips Cobalt Networks' Microservers 10.0
dreamcast sh3 Sega Dreamcast game console 10.0
epoc32 arm 32bit PSION EPOC PDA 10.0
emips mips Machines based on "Extensible MIPS" 10.0
evbsh3 sh3 Evaluation boards with Renesas (Hitachi) Super-H SH3 and SH4 CPUs 10.0
ews4800mips mips NEC's MIPS based EWS4800 workstations 10.0
hp300 m68k Hewlett-Packard 9000/300 and 400 series 10.0
hppa hppa Hewlett-Packard 9000/700 series 10.0
hpcmips mips MIPS based Windows CE PDA machines 10.0
hpcsh sh3 Renesas (Hitachi) SH3 and SH4 based Windows CE PDA machines 10.0
ia64 itanium Itanium family of processors none
ibmnws powerpc IBM Network Station Series 1000 10.0
iyonix arm Iyonix ARM pc 10.0
landisk sh3 SH4 based NAS appliances by I-O DATA 10.0
luna68k m68k OMRON Tateisi Electronics' LUNA series 10.0
mac68k m68k Apple Macintosh 10.0
macppc powerpc Apple Power Macintosh and clones 10.0
mipsco mips Mips family of workstations and servers 10.0
mmeye sh3 Brains' mmEye Multi Media Server 10.0
mvme68k m68k Motorola MVME 68k SBCs 10.0
mvmeppc powerpc Motorola MVME PowerPC SBCs 10.0
netwinder arm StrongARM based NetWinder machines 10.0
news68k m68k Sony's m68k based "NET WORK STATION" series 10.0
newsmips mips Sony's MIPS based "NET WORK STATION" series 10.0
next68k m68k NeXT 68k 'black' hardware 10.0
ofppc powerpc Generic OpenFirmware compliant PowerPC machines 10.0
pmax mips Digital MIPS-based DECstations and DECsystems 10.0
prep powerpc PReP (PowerPC Reference Platform) and CHRP machines 10.0
riscv riscv RISC-V none
rs6000 powerpc MCA-based IBM RS/6000 workstations 10.0
sandpoint powerpc Motorola Sandpoint reference platform 10.0
sbmips mips Broadcom SiByte evaluation boards 10.0
sgimips mips Silicon Graphics' MIPS-based workstations 10.0
shark arm Digital DNARD ("shark") 10.0
sparc sparc Sun SPARC (32-bit) 10.0
sun2 m68k Sun 2 10.0
sun3 m68k Sun 3 and 3x 10.0
vax vax Digital VAX 10.0
x68k m68k Sharp X680x0 series 10.0
zaurus arm Sharp C7x0/C860/C1000/C3x00 series PDA 10.0

Tier III: Life Support -- severely incapacitated or broken

Ports are moved to life support if they no longer function. The reasons can range from lack of community interest to the hardware becoming so rare that it is simply not available any more. If ports in life support are not shown to be working within a reasonable timeframe, they will be moved to the Attic. The guidelines are as follows:

Currently there are no ports with Tier III status.

Ports by CPU architectures

This table contains the same set of ports as in the above list, but ordered by MACHINE_ARCH CPU architecture value (returned by 'uname -p') and showing a total of 16 CPU types. Machines of the same MACHINE_ARCH share the same userland binaries (with a few device specific exceptions). Both big endian (eb) and little endian (el) MIPS and SH3 ports are supported.

CPU Tier(s) Ports(s)
aarch64 I aarch64
alpha II alpha
arm I, II acorn32 cats epoc32 evbarm hpcarm iyonix netwinder shark zaurus
hppa II hppa
i386 I i386 xen
m68010 II sun2
m68k II amiga atari cesfic hp300 luna68k mac68k mvme68k news68k next68k sun3 x68k
mipseb I, II emips evbmips ews4800mips mipsco newsmips sbmips sgimips
mipsel I, II algor arc cobalt evbmips hpcmips pmax sbmips
powerpc I, II amigappc bebox evbppc ibmnws macppc mvmeppc ofppc prep rs6000 sandpoint
sh3eb II evbsh3 mmeye
sh3el II dreamcast evbsh3 landisk hpcsh
sparc II sparc
sparc64 I sparc64 (Can also run sparc binaries)
vax II vax
x86_64 I amd64 (Can also run i386 binaries), xen

Various ways of denoting ports and CPUs

When discussing ports and CPUs, there are two concepts, each of which have three ways of being named. Strictly, the word port refers to the value shown by "uname -m", and typically corresponds to a directory under src/sys. supports aliases, which are passed as if they were a port, but expand to a port and a cpu (MACHINE and MACHINE_ARCH); an example is evbearmv7hf-el which expands to the evbarm port and earmv7hf cpu.

concept /usr/share/mk variable uname
port MACHINE uname -m -m
cpu MACHINE_ARCH uname -p -a

Additonally, there are things referred to as ports which are not actually "uname -m" values, but are notably different than what would be expected from that port name. One is xen, which is a system architecture variant of i386/amd64, and another is aarch64, which is a CPU type variant of evbarm.