Docs / Boards

Arduino Nano 33 IoT: specs and pinout

Nano-format board with an ATSAMD21G18A Arm Cortex-M0+ processor, a NINA-W102 Wi-Fi and Bluetooth LE module, a 6-axis IMU and a crypto chip. It runs at 3.3 V.

Every value cites its sourceOfficial pinout

Buy on Compoden

Specs

Spec	Value	Source
Processor	ATSAMD21G18A Arm Cortex-M0+, up to 48 MHz	Arduino official documentation Section 3.2 Processor, p.7
Flash	256 kB	Arduino official documentation Features, p.2
Wi-Fi / Bluetooth	NINA-W102 module: IEEE 802.11 b/g/n, 2.4 GHz; Bluetooth BR/EDR and Bluetooth Low Energy	Arduino official documentation Features, p.3
I/O voltage	3.3 V only; NOT 5 V tolerant; the 5V pin does not supply voltage (it connects to USB power through a jumper)	Arduino official documentation Section 1 The Board, p.5
Maximum input voltage	-0.3 V to 21 V on the VIN pad (also listed for USB)	Arduino official documentation Section 2.2 Power Consumption, p.5
Operating temperature	-40 C to 85 C (conservative thermal limits for the whole board)	Arduino official documentation Section 2.1, p.5
ADC / DAC	12-bit 350 ksps ADC (up to 16 bit with oversampling); 10-bit 350 ksps DAC	Arduino official documentation Features, p.2
IMU	6-axis IMU (the datasheet names two parts: LSM6DSOX on the board topology and LSM6DSL in the feature and library lists)	Arduino official documentation Section 3.1 Board Topology U3, p.6; Section 3.5, p.8
Communication	6x SERCOM (USART, I2C, SPI, LIN); full-speed USB host/device; two-channel I2S	Arduino official documentation Features, p.2

Power

	Value	Source
Supply	USB, VIN or VUSB pins; maximum input 21 V	Arduino official documentation Section 2.2, p.5: PMax listed as TBC

Pinout

Pin rows are from the official Arduino Nano 33 IoT datasheet (SKU ABX00027). The header pin table is identical to the one in the Nano 33 BLE Sense datasheet.

Pin	Function	Voltage	Notes	Source
1	D13	3.3 V logic	GPIO	Arduino official documentation Section 5.2 Headers, p.11
2	+3V3	3.3 V	Internally generated power output to external devices	Arduino official documentation Section 5.2 Headers, p.11
3	AREF	3.3 V logic	Analog Reference; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
4	A0/DAC0	3.3 V logic	ADC in/DAC out; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
5	A1	3.3 V logic	ADC in; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
6	A2	3.3 V logic	ADC in; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
7	A3	3.3 V logic	ADC in; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
8	A4/SDA	3.3 V logic	ADC in; I2C SDA; Can be used as GPIO A4/A5 have an internal pull-up and default to I2C	Arduino official documentation Section 5.2 Headers, p.11
9	A5/SCL	3.3 V logic	ADC in; I2C SCL; Can be used as GPIO A4/A5 have an internal pull-up and default to I2C	Arduino official documentation Section 5.2 Headers, p.11
10	A6	3.3 V logic	ADC in; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
11	A7	3.3 V logic	ADC in; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
12	VUSB		Normally NC; can be connected to VUSB pin of the USB connector by shorting a jumper	Arduino official documentation Section 5.2 Headers, p.11
13	RST		Active low reset input (duplicate of pin 18)	Arduino official documentation Section 5.2 Headers, p.11
14	GND		Power Ground	Arduino official documentation Section 5.2 Headers, p.11
15	VIN		Vin Power input	Arduino official documentation Section 5.2 Headers, p.11
16	TX	3.3 V logic	USART TX; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
17	RX	3.3 V logic	USART RX; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
18	RST		Active low reset input (duplicate of pin 13)	Arduino official documentation Section 5.2 Headers, p.11
19	GND		Power Ground	Arduino official documentation Section 5.2 Headers, p.11
20	D2	3.3 V logic	GPIO	Arduino official documentation Section 5.2 Headers, p.11
21	D3/PWM	3.3 V logic	GPIO; can be used as PWM	Arduino official documentation Section 5.2 Headers, p.11
22	D4	3.3 V logic	GPIO	Arduino official documentation Section 5.2 Headers, p.11
23	D5/PWM	3.3 V logic	GPIO; can be used as PWM	Arduino official documentation Section 5.2 Headers, p.11
24	D6/PWM	3.3 V logic	GPIO, can be used as PWM	Arduino official documentation Section 5.2 Headers, p.11
25	D7	3.3 V logic	GPIO	Arduino official documentation Section 5.2 Headers, p.11
26	D8	3.3 V logic	GPIO	Arduino official documentation Section 5.2 Headers, p.11
27	D9/PWM	3.3 V logic	GPIO; can be used as PWM	Arduino official documentation Section 5.2 Headers, p.11
28	D10/PWM	3.3 V logic	GPIO; can be used as PWM	Arduino official documentation Section 5.2 Headers, p.11
29	D11/MOSI	3.3 V logic	SPI MOSI; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11
30	D12/MISO	3.3 V logic	SPI MISO; can be used as GPIO	Arduino official documentation Section 5.2 Headers, p.11

Build with it

Project ideas for the Arduino Nano 33 IoT. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.

Wi-Fi temperature logger: The board has built-in Wi-Fi; a digital 1-Wire sensor needs one pin and runs from the 3.3 V pin, matching the board's 3.3 V I/O.
Wi-Fi plant moisture monitor: Power the sensor from 3.3 V so its analog output stays within the board's 3.3 V logic level; the 12-bit ADC reads it.
Weather node with display: Both modules use I2C on A4/A5 at 3.3 V; Wi-Fi sends readings out. Check each module's supply and logic level.
Shake and tilt alert logger: The 6-axis IMU is on the board; the LED needs a series resistor. Learning project.

Common mistakes

Connecting 5 V signals: the board supports 3.3 V I/O only and is not 5 V tolerant (source: Arduino official documentation Section 1)
Expecting the 5V pin to output 5 V: it is connected to USB power through a jumper and does not supply voltage (source: Arduino official documentation Section 1)
Using A4 or A5 as analog inputs: they have an internal pull-up and default to I2C (source: Arduino official documentation Section 3.2)

Not covered by the official source

Supply current is listed TBC in the datasheet.
The Features list shows '32 kB Flash' as a second memory line, which may be a mislabelled SRAM figure; SRAM is not stated.
Radio values are only those printed in the Arduino datasheet; the NINA-W102 module datasheet is not covered here.
The datasheet contradicts itself on the IMU part: LSM6DSOX (Section 3.1 board topology, BOM U3) and LSM6DSL (feature list and library table). The part is not stated here; use the 6-axis IMU library that matches your board.

Sources

Arduino official documentation (Arduino Nano 33 IoT User Manual, SKU ABX00027, modified 07/11/2026)