As of 2017 Zeep is the better option for async SOAP in Python.

Asyncio PySimpleSOAP

The aiopss package is a fork of PySimpleSoap v1.16 and offers a SOAP client for asyncio PEP-3146.

The fork has been modified by replacing internal functions with coroutines and aiohttp has been used to develop the underlying transport layer.

Below is shown an example of how to use the client, it is pretty straight forward. For more documentation consult the PySimpleSoap project.

Note that there is a strange bug in PySimpleSoap with python3, when collections are returned.

from aiopss.client import AsyncSoapClient
from datetime import datetime
import asyncio


@asyncio.coroutine
def example():
    client = AsyncSoapClient(
        wsdl="http://example.com/soap.wsdl",
        location="http://localhost:5000/testendpoint"
    )

    yield from client.connect()
    response = yield from client.receiveSMSStatuses(
        username='jonas',
        password='password',
        statuses=[
            {'Status':
                {
                    'messageID': 1,
                    'countryCode': 45,
                    'number': '26159917',
                    'latestStatus': datetime.today(),
                    'statusCode': '1',
                    'errorCode': '2',
                }
            }
        ]
    )
    print(response)

loop = asyncio.get_event_loop()
loop.run_until_complete(example())
loop.close()